$110+ Cheap flights from Montana to Illinois
This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 4/13. Fares are subject to change and may not be available on all flights or dates of travel.
BZN — ORD
Apr 15 — Apr 221
Round-trip
1 adult, Economy
We work with more than 300 partners to bring you better travel deals
Find cheap flights from Montana to Illinois with Cheapflights
1. Tell us where you want to go
Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”2. Select your favorite providers
We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.3. Compare prices and book
Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.Cheap flight deals from Montana to Illinois
Cheapest
Best
Last-minute
One-way
Cheapest flights from Montana to IllinoisExplore the most affordable flight options available from Montana to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on March 16, 2026.
Explore the most affordable flight options available from Montana to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on March 16, 2026.
This Delta deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/76:25 am
BIL
- MDW
2 stops10h 29m
Delta
Fri 4/102:05 pm
MDW
- BIL
1 stop7h 14m
Delta
Deal found 3/12![Delta logo]()
$254
This Southwest deal was found by Cheapflights users on 3/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 4/53:30 pm
BZN
- STL
1 stop8h 50m
Southwest
Thu 4/308:25 am
STL
- BZN
1 stop8h 15m
Southwest
Deal found 3/13![Southwest logo]()
$256
This Delta deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/165:30 am
BZN
- STL
1 stop6h 53m
Delta
Sun 4/196:20 am
STL
- BZN
1 stop7h 14m
Delta
Deal found 3/12![Delta logo]()
$257
This American Airlines deal was found by Cheapflights users on 3/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/142:02 pm
BIL
- ORD
Nonstop2h 58m
American Airlines
Mon 10/199:40 am
ORD
- BIL
Nonstop3h 02m
American Airlines
Deal found 3/13![American Airlines logo]()
$260
This Alaska Airlines deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/133:04 pm
BZN
- STL
1 stop7h 55m
Alaska Airlines
Wed 4/157:00 am
STL
- BZN
1 stop12h 46m
Alaska Airlines
Deal found 3/11![Alaska Airlines logo]()
$264
This American Airlines deal was found by Cheapflights users on 3/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 4/47:00 am
BZN
- ORD
Nonstop3h 11m
American Airlines
Sun 4/510:09 am
ORD
- BZN
Nonstop3h 29m
American Airlines
Deal found 3/14![American Airlines logo]()
$268
This American Airlines deal was found by Cheapflights users on 3/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/304:57 pm
BZN
- ORD
Nonstop3h 28m
American Airlines
Mon 6/11:44 pm
ORD
- BZN
Nonstop3h 18m
American Airlines
Deal found 3/13![American Airlines logo]()
$269
This Delta deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/155:45 am
BIL
- ORD
1 stop5h 36m
Delta
Sat 8/223:50 pm
ORD
- BIL
1 stop7h 47m
Delta
Deal found 3/11![Delta logo]()
$271
This Southwest deal was found by Cheapflights users on 3/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/134:20 pm
BZN
- STL
1 stop6h 30m
Southwest
Fri 4/175:15 pm
STL
- BZN
1 stop6h 45m
Southwest
Deal found 3/13![Southwest logo]()
$275
This Delta deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/95:35 am
BIL
- ORD
1 stop5h 17m
Delta
Wed 5/132:00 pm
ORD
- BIL
2 stops10h 06m
Delta
Deal found 3/11![Delta logo]()
$276
This Delta deal was found by Cheapflights users on 3/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/105:20 am
BZN
- STL
1 stop6h 57m
Delta
Mon 4/136:19 am
STL
- BZN
1 stop7h 15m
Delta
Deal found 3/13![Delta logo]()
$277
This Alaska Airlines deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/233:49 pm
BZN
- ORD
1 stop7h 10m
Alaska Airlines
Sat 4/256:00 am
ORD
- BZN
1 stop14h 19m
Alaska Airlines
Deal found 3/11![Alaska Airlines logo]()
$277
Best flights from Montana to IllinoisDiscover carefully curated flight deals from Montana to Illinois that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated March 16, 2026.
Discover carefully curated flight deals from Montana to Illinois that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated March 16, 2026.
This Delta deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/165:30 am
BZN
- STL
1 stop6h 53m
Delta
Sun 4/196:20 am
STL
- BZN
1 stop7h 14m
Delta
Deal found 3/12![Delta logo]()
$257
This Southwest deal was found by Cheapflights users on 3/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/236:15 am
BZN
- ORD
1 stop6h 40m
Southwest
Mon 4/276:15 pm
ORD
- BZN
1 stop5h 45m
Southwest
Deal found 3/15![Southwest logo]()
$284
This Alaska Airlines deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 4/253:55 pm
MSO
- STL
1 stop7h 04m
Alaska Airlines
Wed 4/297:00 am
STL
- MSO
1 stop8h 59m
Alaska Airlines
Deal found 3/11![Alaska Airlines logo]()
$297
This United Airlines deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/215:00 pm
FCA
- ORD
1 stop5h 59m
United Airlines
Fri 8/288:40 am
ORD
- FCA
Nonstop3h 46m
United Airlines
Deal found 3/12![United Airlines logo]()
$299
This American Airlines deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/131:51 pm
MSO
- MLI
1 stop8h 31m
American Airlines
Sun 8/166:00 am
MLI
- MSO
1 stop7h 16m
American Airlines
Deal found 3/11![American Airlines logo]()
$384
This Delta deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/95:35 am
BIL
- ORD
1 stop5h 17m
Delta
Wed 5/132:00 pm
ORD
- BIL
2 stops10h 06m
Delta
Deal found 3/11![Delta logo]()
$276
This Southwest deal was found by Cheapflights users on 3/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/104:20 pm
BZN
- MDW
1 stop6h 20m
Southwest
Mon 4/135:15 pm
MDW
- BZN
1 stop6h 45m
Southwest
Deal found 3/15![Southwest logo]()
$289
This Alaska Airlines deal was found by Cheapflights users on 3/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 4/253:55 pm
MSO
- ORD
1 stop7h 04m
Alaska Airlines
Wed 4/296:00 am
ORD
- MSO
1 stop9h 59m
Alaska Airlines
Deal found 3/13![Alaska Airlines logo]()
$297
This United Airlines deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/82:40 pm
BZN
- ORD
1 stop7h 18m
United Airlines
Sun 5/109:01 am
ORD
- BZN
Nonstop3h 25m
United Airlines
Deal found 3/11![United Airlines logo]()
$300
This Delta deal was found by Cheapflights users on 3/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/76:25 am
BIL
- MDW
2 stops10h 29m
Delta
Fri 4/101:10 pm
MDW
- BIL
2 stops10h 19m
Delta
Deal found 3/14![Delta logo]()
$280
This Southwest deal was found by Cheapflights users on 3/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/1511:20 am
BZN
- ORD
2 stops11h 35m
Southwest
Fri 4/176:15 pm
ORD
- BZN
1 stop5h 45m
Southwest
Deal found 3/14![Southwest logo]()
$294
This United Airlines deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/74:29 pm
BZN
- ORD
1 stop5h 50m
United Airlines
Sun 8/95:00 am
ORD
- BZN
1 stop5h 29m
United Airlines
Deal found 3/11![United Airlines logo]()
$306
This Delta deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/86:35 pm
BZN
- STL
1 stop4h 55m
Delta
Mon 5/117:59 pm
STL
- BZN
1 stop5h 00m
Delta
Deal found 3/11![Delta logo]()
$288
This Southwest deal was found by Cheapflights users on 3/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/106:15 am
BZN
- STL
1 stop12h 30m
Southwest
Mon 4/135:15 pm
STL
- BZN
1 stop6h 45m
Southwest
Deal found 3/13![Southwest logo]()
$306
This Delta deal was found by Cheapflights users on 3/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/96:30 am
BIL
- MDW
1 stop5h 49m
Delta
Tue 5/127:13 pm
MDW
- BIL
1 stop5h 01m
Delta
Deal found 3/15![Delta logo]()
$291
This American Airlines deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/214:54 pm
FCA
- ORD
Nonstop3h 22m
American Airlines
Fri 8/281:35 pm
ORD
- FCA
Nonstop3h 39m
American Airlines
Deal found 3/12![American Airlines logo]()
$396
This Alaska Airlines deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 5/271:25 pm
FCA
- ORD
Nonstop3h 39m
Alaska Airlines
Sat 5/309:45 am
ORD
- FCA
Nonstop3h 51m
Alaska Airlines
Deal found 3/11![Alaska Airlines logo]()
$369
This United Airlines deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 3/312:40 pm
BZN
- STL
1 stop5h 14m
United Airlines
Sat 4/48:54 am
STL
- BZN
1 stop7h 40m
United Airlines
Deal found 3/11![United Airlines logo]()
$345
This Southwest deal was found by Cheapflights users on 3/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/96:15 am
BZN
- MDW
2 stops10h 00m
Southwest
Mon 4/135:15 pm
MDW
- BZN
1 stop6h 45m
Southwest
Deal found 3/15![Southwest logo]()
$319
This Delta deal was found by Cheapflights users on 3/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/96:27 am
BIL
- MDW
1 stop5h 52m
Delta
Wed 5/137:13 pm
MDW
- BIL
1 stop4h 53m
Delta
Deal found 3/13![Delta logo]()
$291
This Alaska Airlines deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 4/197:00 am
MSO
- ORD
1 stop22h 39m
Alaska Airlines
Tue 4/216:00 am
ORD
- MSO
1 stop7h 31m
Alaska Airlines
Deal found 3/12![Alaska Airlines logo]()
$377
This United Airlines deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/82:37 pm
MSO
- STL
1 stop5h 06m
United Airlines
Sun 5/102:35 pm
STL
- MSO
1 stop7h 55m
United Airlines
Deal found 3/12![United Airlines logo]()
$348
This Delta deal was found by Cheapflights users on 3/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/95:30 am
BIL
- ORD
1 stop5h 22m
Delta
Tue 5/125:41 pm
ORD
- BIL
1 stop6h 33m
Delta
Deal found 3/15![Delta logo]()
$291
This Southwest deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/216:40 am
BZN
- MDW
Nonstop2h 50m
Southwest
Sat 7/2512:50 pm
MDW
- BZN
2 stops10h 05m
Southwest
Deal found 3/12![Southwest logo]()
$337
This United Airlines deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/115:00 am
BIL
- ORD
1 stop5h 28m
United Airlines
Fri 8/218:40 am
ORD
- BIL
Nonstop3h 22m
United Airlines
Deal found 3/11![United Airlines logo]()
$350
This Delta deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 4/267:18 am
BZN
- ORD
1 stop8h 21m
Delta
Wed 4/295:04 pm
ORD
- BZN
2 stops8h 05m
Delta
Deal found 3/11![Delta logo]()
$294
This Southwest deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 4/264:25 pm
BZN
- MDW
2 stops7h 25m
Southwest
Sun 5/36:00 am
MDW
- BZN
1 stop5h 25m
Southwest
Deal found 3/12![Southwest logo]()
$342
This Delta deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 5/195:30 am
MSO
- ORD
1 stop5h 22m
Delta
Sat 5/235:41 pm
ORD
- MSO
1 stop6h 59m
Delta
Deal found 3/11![Delta logo]()
$309
This United Airlines deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/1012:34 pm
MSO
- ORD
Nonstop3h 31m
United Airlines
Sat 7/186:00 am
ORD
- MSO
1 stop8h 19m
United Airlines
Deal found 3/11![United Airlines logo]()
$379
This Southwest deal was found by Cheapflights users on 3/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/311:50 pm
BZN
- MDW
1 stop8h 35m
Southwest
Tue 8/46:50 am
MDW
- BZN
1 stop7h 35m
Southwest
Deal found 3/10![Southwest logo]()
$358
Last-minute flights from Montana to IllinoisDiscover last-minute flight deals from Montana to Illinois. Data last updated March 16, 2026 and is based on user searches.
Discover last-minute flight deals from Montana to Illinois. Data last updated March 16, 2026 and is based on user searches.
This United Airlines deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 3/2712:44 pm
BZN
- STL
1 stop7h 39m
United Airlines
Tue 3/318:30 am
STL
- BZN
1 stop7h 53m
United Airlines
Deal found 3/12![United Airlines logo]()
$279
This American Airlines deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/21:49 pm
BZN
- ORD
Nonstop3h 09m
American Airlines
Sat 4/185:00 am
ORD
- BZN
1 stop8h 53m
American Airlines
Deal found 3/11![American Airlines logo]()
$279
This American Airlines deal was found by Cheapflights users on 3/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 4/47:00 am
BZN
- ORD
Nonstop3h 11m
American Airlines
Sun 4/510:09 am
ORD
- BZN
Nonstop3h 29m
American Airlines
Deal found 3/14![American Airlines logo]()
$268
This Southwest deal was found by Cheapflights users on 3/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 4/53:30 pm
BZN
- STL
1 stop8h 50m
Southwest
Thu 4/308:25 am
STL
- BZN
1 stop8h 15m
Southwest
Deal found 3/13![Southwest logo]()
$256
This Delta deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/76:25 am
BIL
- MDW
2 stops10h 29m
Delta
Fri 4/102:05 pm
MDW
- BIL
1 stop7h 14m
Delta
Deal found 3/12![Delta logo]()
$254
This Delta deal was found by Cheapflights users on 3/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/105:20 am
BZN
- STL
1 stop6h 57m
Delta
Mon 4/136:19 am
STL
- BZN
1 stop7h 15m
Delta
Deal found 3/13![Delta logo]()
$277
This Alaska Airlines deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/133:04 pm
BZN
- STL
1 stop7h 55m
Alaska Airlines
Wed 4/157:00 am
STL
- BZN
1 stop12h 46m
Alaska Airlines
Deal found 3/11![Alaska Airlines logo]()
$264
This Southwest deal was found by Cheapflights users on 3/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/134:20 pm
BZN
- STL
1 stop6h 30m
Southwest
Fri 4/175:15 pm
STL
- BZN
1 stop6h 45m
Southwest
Deal found 3/13![Southwest logo]()
$275
This Southwest deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/134:20 pm
BZN
- STL
1 stop6h 30m
Southwest
Wed 4/152:30 pm
STL
- BZN
2 stops8h 25m
Southwest
Deal found 3/11![Southwest logo]()
$280
This Delta deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/165:30 am
BZN
- STL
1 stop6h 53m
Delta
Sun 4/196:20 am
STL
- BZN
1 stop7h 14m
Delta
Deal found 3/12![Delta logo]()
$257
This Alaska Airlines deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/233:49 pm
BZN
- ORD
1 stop7h 10m
Alaska Airlines
Sat 4/256:00 am
ORD
- BZN
1 stop14h 19m
Alaska Airlines
Deal found 3/11![Alaska Airlines logo]()
$277
This Southwest deal was found by Cheapflights users on 3/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/236:15 am
BZN
- ORD
1 stop6h 40m
Southwest
Mon 4/276:15 pm
ORD
- BZN
1 stop5h 45m
Southwest
Deal found 3/15![Southwest logo]()
$284
One-way flights from Montana to IllinoisSearch for one-way flight options from Montana to Illinois. Find affordable one-way fares based on user searches. Data last updated March 16, 2026.
Search for one-way flight options from Montana to Illinois. Find affordable one-way fares based on user searches. Data last updated March 16, 2026.
This Kiwi.com deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/138:54 pm
MSO
- ORD
1 stop8h 26m
Multiple Airlines
Deal found 3/12![Multiple Airlines logo]()
$110
This Kiwi.com deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 5/118:54 pm
MSO
- ORD
2 stops34h 01m
Multiple Airlines
Deal found 3/11![Multiple Airlines logo]()
$123
This Kiwi.com deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/1310:34 am
BIL
- ORD
1 stop18h 46m
Multiple Airlines
Deal found 3/12![Multiple Airlines logo]()
$124
This Alaska Airlines deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/137:26 pm
BZN
- ORD
1 stop10h 13m
Alaska Airlines
Deal found 3/12![Alaska Airlines logo]()
$125
This United Airlines deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 4/112:35 pm
BIL
- ORD
1 stop7h 23m
United Airlines
Deal found 3/12![United Airlines logo]()
$125
This Southwest deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/44:30 pm
BZN
- STL
1 stop6h 25m
Southwest
Deal found 3/12![Southwest logo]()
$126
This Delta deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/76:25 am
BIL
- ORD
2 stops11h 09m
Delta
Deal found 3/11![Delta logo]()
$130
This Kiwi.com deal was found by Cheapflights users on 3/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/158:54 pm
MSO
- ORD
1 stop7h 31m
Multiple Airlines
Deal found 3/15![Multiple Airlines logo]()
$131
This Alaska Airlines deal was found by Cheapflights users on 3/11. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/83:00 pm
BZN
- ORD
1 stop7h 59m
Alaska Airlines
Deal found 3/11![Alaska Airlines logo]()
$133
This Southwest deal was found by Cheapflights users on 3/12. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/117:35 am
BZN
- MDW
Nonstop2h 50m
Southwest
Deal found 3/12![Southwest logo]()
$135
This American Airlines deal was found by Cheapflights users on 3/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/64:54 pm
BZN
- ORD
Nonstop3h 09m
American Airlines
Deal found 3/13![American Airlines logo]()
$135
This Kiwi.com deal was found by Cheapflights users on 3/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/178:54 pm
MSO
- ORD
1 stop7h 31m
Multiple Airlines
Deal found 3/14![Multiple Airlines logo]()
$138
Find flight deals from Montana to Illinois
Keep the following information in mind while searching for Montana to Illinois flight deals. Data was last updated March 16, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $254 (Delta) |
One-way from | $110 (Kiwi.com) |
Popular in | May |
Cheapest in | September |
Average price | $279 |
Good round-trip deal | $322 or less |
Good one-way deal | $202 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from Montana to Illinois that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated March 16, 2026.
Use the filters below to find and compare flights from Montana to Illinois that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
BozemanSt. Louis
BZN - STL
BZNSTL
Bozeman Gallatin Field
Thu 4/16
5:30 am-1:23 pm
1 stop6h 53m
Lambert-St Louis
Sun 4/19
6:20 am-12:34 pm
1 stop7h 14m
$257
BillingsChicago
BIL - ORD
BILORD
Billings Logan Intl
Sat 5/9
5:35 am-11:52 am
1 stop5h 17m
Chicago O'Hare Intl
Wed 5/13
2:00 pm-11:06 pm
2 stops10h 06m
$276
BillingsChicago
BIL - MDW
BILMDW
Billings Logan Intl
Tue 4/7
6:25 am-5:54 pm
2 stops10h 29m
Chicago Midway
Fri 4/10
1:10 pm-10:29 pm
2 stops10h 19m
$280
BozemanChicago
BZN - ORD
BZNORD
Bozeman Gallatin Field
Thu 4/23
6:15 am-1:55 pm
1 stop6h 40m
Chicago O'Hare Intl
Mon 4/27
6:15 pm-11:00 pm
1 stop5h 45m
$284
BozemanSt. Louis
BZN - STL
BZNSTL
Bozeman Gallatin Field
Fri 5/8
6:35 pm-12:30 am
1 stop4h 55m
Lambert-St Louis
Mon 5/11
7:59 pm-11:59 pm
1 stop5h 00m
$288
BozemanChicago
BZN - MDW
BZNMDW
Bozeman Gallatin Field
Fri 4/10
4:20 pm-11:40 pm
1 stop6h 20m
Chicago Midway
Mon 4/13
5:15 pm-11:00 pm
1 stop6h 45m
$289
BillingsChicago
BIL - MDW
BILMDW
Billings Logan Intl
Sat 5/9
6:30 am-1:19 pm
1 stop5h 49m
Chicago Midway
Tue 5/12
7:13 pm-11:14 pm
1 stop5h 01m
$291
BillingsChicago
BIL - MDW
BILMDW
Billings Logan Intl
Sat 5/9
6:27 am-1:19 pm
1 stop5h 52m
Chicago Midway
Wed 5/13
7:13 pm-11:06 pm
1 stop4h 53m
$291
BillingsChicago
BIL - ORD
BILORD
Billings Logan Intl
Sat 5/9
5:30 am-11:52 am
1 stop5h 22m
Chicago O'Hare Intl
Tue 5/12
5:41 pm-11:14 pm
1 stop6h 33m
$291
BozemanChicago
BZN - ORD
BZNORD
Bozeman Gallatin Field
Wed 4/15
11:20 am-11:55 pm
2 stops11h 35m
Chicago O'Hare Intl
Fri 4/17
6:15 pm-11:00 pm
1 stop5h 45m
$294
Showing 1-10 of 60 resultsSorted by cheapest first
Best time to book a flight from Montana to Illinois
Have a flexible travel schedule? Discover the best time to fly to Illinois from Montana with our price prediction graph.
BIL-MDW
BZN-STL
BZN-ORD
BIL-ORD
FCA-ORD
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.
Cheapflights Insights
Everything you need to know about your flight from Montana to Illinois
USMT-USIL
BIL-MDW
BZN-STL
BZN-ORD
BIL-ORD
What is the cheapest month to book a flight from Montana to Illinois?
Currently, October is the cheapest month in which you can book a flight from Montana to Illinois (average of $169). Flying from Montana to Illinois in November is currently the most expensive (average of $298). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.
What is the cheapest time of day to fly from MT to IL?
Find hourly flight availability from Montana to Illinois. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated March 16, 2026.
When flying from Montana to Illinois, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.
Weekly flight availability from Montana to Illinois
Explore weekly flight availability from Montana to Illinois. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated March 16, 2026.
The most flights from USMT to USIL are scheduled on a Saturday (10 on average). You will have fewer flight options on Thursday, which is when the least amount of flights are scheduled (3 on average).
Reviews of airlines servicing Illinois
Get insights into the airlines that provide service to Illinois. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Illinois. Reviews last updated March 16, 2026.
Get a feel of what it's like to fly with Alaska Airlines,Delta, andUnited Airlines from Montana to Illinois by reading reviews from past customers. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Comfort
7.8
Crew
8.5
Entertainment
7.0
Overall
7.9
Boarding
8.1
Food
7.1
Reviews
1 / 20
10.0
ExcellentFranzi,Mar 2026
SFO - PDX
Comfort
7.8
Crew
8.5
Entertainment
7.0
Overall
7.9
Boarding
8.1
Food
7.1
Reviews
1 / 20
10.0
ExcellentFranzi,Mar 2026
SFO - PDX
Comfort
7.8
Crew
8.5
Entertainment
7.0
Overall
7.9
Boarding
8.1
Food
7.1
Reviews
1 / 20
10.0
ExcellentFranzi,Mar 2026
SFO - PDX
Comfort
7.8
Crew
8.5
Entertainment
7.0
Overall
7.9
Boarding
8.1
Food
7.1
Reviews
1 / 20
10.0
ExcellentFranzi,Mar 2026
SFO - PDX
Comfort
7.8
Crew
8.5
Entertainment
7.0
Overall
7.9
Boarding
8.1
Food
7.1
Reviews
1 / 20
10.0
ExcellentFranzi,Mar 2026
SFO - PDX
Related info for your journey
Find useful and relevant information for your journey from Montana to Illinois. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
Browse thousands of different options on Cheapflights for your next trip
Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.
Alternative routes
Complete your trip
Flights by cabin class
Other flight options
Popular flights
Return Flight Options
Top destinations
Alternative routes for Montana to Illinois
See prices for flight routes from nearby airports that may be better suited for you.
Complete your trip
Complete your trip to Illinois by adding a car rental and/or hotel reservation to your travel itinerary.
Search flights from Montana to Illinois by cabin class
Find flights from Montana to Illinois, based on your preferred cabin class, be it economy, premium economy, business, or first class.
Montana and Illinois flights
Browse other Montana and Illinois flight options. Last updated on March 16, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
Find a return flight route from Illinois
Find the right flight back to Montana after your stay in Illinois
Montana to Illinois flights
Consider these flights traveling from Montana to Illinois.
Top 4 airlines flying from Montana to Illinois
Discover the top 4 airlines that operate flights from Montana to Illinois. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated March 16, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$187 | Average$442 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$191 | Average$327 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$230 | Average$446 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$349 | Average$469 | FlexibilityNo cancel fee | On-time75% |