$119+ Cheap flights from Ontario (ONT) to Illinois
This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 12/16. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — ORD
Nov 5 — Nov 121
Round-trip
1 adult, Economy
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Find cheap flights from Ontario 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 Ontario to Illinois
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Cheapest flights from Ontario to IllinoisExplore the most affordable flight options available from Ontario to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on October 6, 2026.
Explore the most affordable flight options available from Ontario to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on October 6, 2026.
This Cheapflightsfares deal was found by Cheapflights users on 10/2. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/36:25 am -
1 stop15h 56m
Mon 11/95:15 pm -
1 stop18h 25m
Deal found 10/2![Frontier logo]()
$198
This Frontier deal was found by Cheapflights users on 10/1. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/28:03 pm -
1 stop13h 19m
Thu 11/512:20 pm -
1 stop8h 48m
Deal found 10/1![Frontier logo]()
$200
This Frontier deal was found by Cheapflights users on 10/1. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/28:03 pm -
1 stop11h 32m
Thu 11/56:30 am -
1 stop6h 05m
Deal found 10/1![Frontier logo]()
$200
This Frontier deal was found by Cheapflights users on 10/5. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/58:35 pm -
1 stop6h 38m
Thu 11/1210:29 am -
1 stop10h 39m
Deal found 10/5![Frontier logo]()
$201
This Cheapflightsfares deal was found by Cheapflights users on 10/2. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/3111:52 am -
1 stop10h 29m
Tue 11/36:30 am -
1 stop19h 21m
Deal found 10/2![Frontier logo]()
$205
This Booking.com deal was found by Cheapflights users on 10/6. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/311:52 am -
1 stop10h 29m
Tue 11/108:59 am -
1 stop9h 39m
Deal found 10/6![Frontier logo]()
$206
This Super.com deal was found by Cheapflights users on 10/6. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/36:00 am -
1 stop16h 53m
Mon 12/76:21 am -
1 stop7h 30m
Deal found 10/6![Frontier logo]()
$207
This Gotogate deal was found by Cheapflights users on 10/5. 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 Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/138:35 pm -
1 stop6h 38m
Mon 11/165:15 pm -
1 stop18h 25m
Deal found 10/5![Frontier logo]()
$208
This FlightHub deal was found by Cheapflights users on 10/6. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/108:29 am -
1 stop18h 32m
Tue 12/156:21 am -
1 stop7h 30m
Deal found 10/6![Frontier logo]()
$209
This CheapOair deal was found by Cheapflights users on 10/5. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/58:35 pm -
1 stop6h 38m
Mon 11/165:15 pm -
1 stop18h 25m
Deal found 10/5![Frontier logo]()
$210
This CheapOair deal was found by Cheapflights users on 10/5. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/2410:40 pm -
1 stop28h 30m
Tue 12/16:21 am -
1 stop7h 11m
Deal found 10/5![Frontier logo]()
$211
This Booking.com deal was found by Cheapflights users on 10/6. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/46:30 am -
1 stop15h 51m
Mon 11/95:15 pm -
1 stop18h 25m
Deal found 10/6![Frontier logo]()
$212
Best flights from Ontario to IllinoisDiscover carefully curated flight deals from Ontario to Illinois that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated October 6, 2026.
Discover carefully curated flight deals from Ontario to Illinois that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated October 6, 2026.
This KAYAK deal was found by Cheapflights users on 10/5. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/81:11 pm -
1 stop6h 45m
Wed 12/97:18 pm -
1 stop6h 39m
Deal found 10/5![Delta logo]()
$317
This Southwest deal was found by Cheapflights users on 10/5. 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 11/242:35 pm -
1 stop7h 40m
Tue 12/15:50 am -
1 stop5h 55m
Deal found 10/5![Southwest logo]()
$392
This United Airlines deal was found by Cheapflights users on 10/5. 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.
Sun 11/16:57 am -
Nonstop4h 02m
Mon 11/26:00 am -
1 stop8h 29m
Deal found 10/5![United Airlines logo]()
$413
This American Airlines deal was found by Cheapflights users on 10/3. 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 10/232:22 pm -
1 stop7h 01m
Sat 10/314:42 pm -
1 stop6h 29m
Deal found 10/3![American Airlines logo]()
$414
This Delta deal was found by Cheapflights users on 10/4. 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 10/186:20 am -
1 stop8h 33m
Tue 10/277:35 am -
1 stop7h 01m
Deal found 10/4![Delta logo]()
$317
This Delta deal was found by Cheapflights users on 10/4. 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 10/296:00 am -
2 stops8h 32m
Fri 11/65:27 am -
1 stop7h 39m
Deal found 10/4![Delta logo]()
$322
This Alaska Airlines deal was found by Cheapflights users on 10/6. 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 10/156:56 pm -
2 stops13h 55m
Tue 10/2011:21 am -
2 stops10h 54m
Deal found 10/6![Alaska Airlines logo]()
$729
This Delta deal was found by Cheapflights users on 10/4. 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 10/206:00 pm -
2 stops13h 32m
Tue 10/2710:12 am -
2 stops14h 31m
Deal found 10/4![Delta logo]()
$327
This Southwest deal was found by Cheapflights users on 10/2. 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 12/1111:55 pm -
Nonstop3h 45m
Tue 12/1512:05 pm -
1 stop6h 05m
Deal found 10/2![Southwest logo]()
$399
This Delta deal was found by Cheapflights users on 10/4. 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 10/176:00 pm -
2 stops12h 44m
Tue 10/2710:12 am -
2 stops14h 31m
Deal found 10/4![Delta logo]()
$327
This Delta deal was found by Cheapflights users on 10/4. 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.
Wed 10/216:00 pm -
2 stops12h 44m
Tue 10/2712:27 pm -
2 stops12h 16m
Deal found 10/4![Delta logo]()
$327
This Southwest deal was found by Cheapflights users on 10/5. 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 10/1311:55 pm -
Nonstop3h 45m
Tue 10/276:05 am -
1 stop6h 40m
Deal found 10/5![Southwest logo]()
$444
This United Airlines deal was found by Cheapflights users on 10/4. 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 1/237:00 am -
1 stop7h 59m
Tue 1/268:00 am -
2 stops12h 03m
Deal found 10/4![United Airlines logo]()
$504
This Delta deal was found by Cheapflights users on 10/3. 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.
Wed 10/286:20 am -
2 stops13h 45m
Tue 11/36:20 am -
2 stops12h 52m
Deal found 10/3![Delta logo]()
$327
This American Airlines deal was found by Cheapflights users on 10/3. 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 10/247:00 am -
1 stop7h 04m
Fri 10/304:38 pm -
1 stop9h 14m
Deal found 10/3![American Airlines logo]()
$533
This United Airlines deal was found by Cheapflights users on 10/5. 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 12/127:00 am -
1 stop8h 58m
Tue 1/510:40 am -
2 stops12h 20m
Deal found 10/5![United Airlines logo]()
$504
This American Airlines deal was found by Cheapflights users on 10/6. 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 10/1511:59 pm -
1 stop9h 04m
Sat 10/244:38 pm -
1 stop6h 43m
Deal found 10/6![American Airlines logo]()
$535
This Delta deal was found by Cheapflights users on 10/5. 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 10/91:35 pm -
1 stop6h 30m
Sun 10/115:27 am -
1 stop7h 39m
Deal found 10/5![Delta logo]()
$338
This Delta deal was found by Cheapflights users on 10/3. 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.
Wed 10/286:00 pm -
2 stops13h 32m
Tue 11/310:12 am -
2 stops14h 31m
Deal found 10/3![Delta logo]()
$348
This United Airlines deal was found by Cheapflights users on 10/3. 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 10/96:32 pm -
1 stop9h 27m
Mon 10/128:20 pm -
Nonstop4h 29m
Deal found 10/3![United Airlines logo]()
$567
This American Airlines deal was found by Cheapflights users on 10/4. 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.
Mon 10/2611:59 pm -
1 stop9h 04m
Sun 11/16:00 am -
2 stops11h 35m
Deal found 10/4![American Airlines logo]()
$584
This United Airlines deal was found by Cheapflights users on 10/5. 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 10/201:22 pm -
1 stop5h 29m
Sat 10/248:45 am -
1 stop6h 01m
Deal found 10/5![United Airlines logo]()
$569
This Delta deal was found by Cheapflights users on 10/6. 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 10/1612:16 pm -
1 stop8h 17m
Mon 10/1912:27 pm -
2 stops13h 28m
Deal found 10/6![Delta logo]()
$364
This United Airlines deal was found by Cheapflights users on 10/5. 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.
Thu 12/2411:52 pm -
Nonstop3h 55m
Mon 12/287:52 pm -
Nonstop4h 39m
Deal found 10/5![United Airlines logo]()
$578
This American Airlines deal was found by Cheapflights users on 10/4. 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 11/252:09 pm -
1 stop5h 53m
Sun 11/294:05 pm -
2 stops10h 07m
Deal found 10/4![American Airlines logo]()
$696
This United Airlines deal was found by Cheapflights users on 10/4. 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.
Mon 10/191:24 pm -
2 stops7h 49m
Sat 12/58:40 am -
2 stops10h 56m
Deal found 10/4![United Airlines logo]()
$589
This Delta deal was found by Cheapflights users on 10/3. 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 10/2311:15 pm -
1 stop9h 03m
Sat 10/311:00 pm -
1 stop8h 30m
Deal found 10/3![Delta logo]()
$414
This American Airlines deal was found by Cheapflights users on 10/2. 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 10/146:00 am -
1 stop6h 07m
Sat 10/177:11 am -
1 stop8h 19m
Deal found 10/2![American Airlines logo]()
$697
This United Airlines deal was found by Cheapflights users on 10/2. 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 11/67:00 am -
Nonstop4h 04m
Sun 11/84:15 pm -
Nonstop4h 32m
Deal found 10/2![United Airlines logo]()
$613
This Delta deal was found by Cheapflights users on 10/3. 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 11/76:00 am -
2 stops8h 26m
Sun 11/86:20 am -
2 stops12h 52m
Deal found 10/3![Delta logo]()
$427
Last-minute flights from Ontario to IllinoisDiscover last-minute flight deals from Ontario to Illinois. Data last updated October 6, 2026 and is based on user searches.
Discover last-minute flight deals from Ontario to Illinois. Data last updated October 6, 2026 and is based on user searches.
This Booking.com deal was found by Cheapflights users on 10/5. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/2711:52 am -
1 stop10h 29m
Fri 10/306:30 am -
1 stop6h 12m
Deal found 10/5![Frontier logo]()
$215
This Cheapflightsfares deal was found by Cheapflights users on 10/5. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/292:23 pm -
1 stop12h 50m
Sun 11/15:15 pm -
1 stop25h 06m
Deal found 10/5![Frontier logo]()
$216
This Cheapflightsfares deal was found by Cheapflights users on 10/2. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/3111:52 am -
1 stop10h 29m
Tue 11/36:30 am -
1 stop19h 21m
Deal found 10/2![Frontier logo]()
$205
This Frontier deal was found by Cheapflights users on 10/1. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/28:03 pm -
1 stop13h 19m
Thu 11/512:20 pm -
1 stop8h 48m
Deal found 10/1![Frontier logo]()
$200
This Frontier deal was found by Cheapflights users on 10/1. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/28:03 pm -
1 stop11h 32m
Thu 11/56:30 am -
1 stop6h 05m
Deal found 10/1![Frontier logo]()
$200
This Cheapflightsfares deal was found by Cheapflights users on 10/2. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/36:25 am -
1 stop15h 56m
Mon 11/95:15 pm -
1 stop18h 25m
Deal found 10/2![Frontier logo]()
$198
This Booking.com deal was found by Cheapflights users on 10/6. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/311:52 am -
1 stop10h 29m
Tue 11/108:59 am -
1 stop9h 39m
Deal found 10/6![Frontier logo]()
$206
This Booking.com deal was found by Cheapflights users on 10/6. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/46:30 am -
1 stop15h 51m
Mon 11/95:15 pm -
1 stop18h 25m
Deal found 10/6![Frontier logo]()
$212
This Frontier deal was found by Cheapflights users on 10/5. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/58:35 pm -
1 stop6h 38m
Thu 11/1210:29 am -
1 stop10h 39m
Deal found 10/5![Frontier logo]()
$201
This CheapOair deal was found by Cheapflights users on 10/5. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/58:35 pm -
1 stop6h 38m
Mon 11/165:15 pm -
1 stop18h 25m
Deal found 10/5![Frontier logo]()
$210
This Gotogate deal was found by Cheapflights users on 10/5. 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 Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/138:35 pm -
1 stop6h 38m
Mon 11/165:15 pm -
1 stop18h 25m
Deal found 10/5![Frontier logo]()
$208
This CheapOair deal was found by Cheapflights users on 10/5. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/2410:40 pm -
1 stop28h 30m
Tue 12/16:21 am -
1 stop7h 11m
Deal found 10/5![Frontier logo]()
$211
One-way flights from Ontario to IllinoisSearch for one-way flight options from Ontario to Illinois. Find affordable one-way fares based on user searches. Data last updated October 6, 2026.
Search for one-way flight options from Ontario to Illinois. Find affordable one-way fares based on user searches. Data last updated October 6, 2026.
This Kiwi.com deal was found by Cheapflights users on 10/2. 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.
Wed 12/1611:30 am -
1 stop29h 52m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 10/2![Frontier logo]()
$119
This Flightnetwork deal was found by Cheapflights users on 10/6. 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 Flightnetwork is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/308:35 pm -
1 stop6h 38m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 10/6![Frontier logo]()
$121
This Delta deal was found by Cheapflights users on 10/5. 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 10/316:00 am -
2 stops10h 00m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 10/5![Delta logo]()
$124
This Cheapflightsfares deal was found by Cheapflights users on 10/5. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 12/411:30 am -
1 stop11h 23m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 10/5![Frontier logo]()
$124
This Super.com deal was found by Cheapflights users on 10/3. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/158:35 pm -
1 stop6h 41m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 10/3![Frontier logo]()
$125
This Super.com deal was found by Cheapflights users on 10/5. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/98:35 pm -
1 stop6h 41m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 10/5![Frontier logo]()
$127
This Mytrip deal was found by Cheapflights users on 10/6. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/168:35 pm -
1 stop6h 41m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 10/6![Frontier logo]()
$129
This Southwest deal was found by Cheapflights users on 10/2. 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 12/174:00 pm -
1 stop6h 10m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 10/2![Southwest logo]()
$130
This Frontier deal was found by Cheapflights users on 10/5. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/298:35 pm -
1 stop6h 38m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 10/5![Frontier logo]()
$130
This Frontier deal was found by Cheapflights users on 10/6. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 11/18:03 pm -
1 stop13h 22m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 10/6![Frontier logo]()
$132
This Delta deal was found by Cheapflights users on 10/5. 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 10/306:00 am -
2 stops10h 00m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 10/5![Delta logo]()
$137
This Jetabroad deal was found by Cheapflights users on 10/6. 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 Jetabroad is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/309:16 am -
1 stop9h 02m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 10/6![Frontier logo]()
$139
Find flight deals from Ontario to Illinois
Keep the following information in mind while searching for Ontario to Illinois flight deals. Data was last updated October 6, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $198 (Cheapflightsfares) |
One-way from | $119 (Kiwi.com) |
Popular in | June |
Cheapest in | November |
Average price | $321 |
Good round-trip deal | $399 or less |
Good one-way deal | $159 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from Ontario 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 7,457,451 searches. Data last updated October 6, 2026.
Use the filters below to find and compare flights from Ontario to Illinois that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
OntarioChicago
ONT Ontario - MDW Chicago Midway
ONTMDW
Ontario
Mon 1/4
7:05 pm-5:00 am
1 stop7h 55m
Chicago Midway
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$150
OntarioChicago
ONT Ontario - MDW Chicago Midway
ONTMDW
Ontario
Tue 10/27
12:16 pm-10:33 pm
1 stop8h 17m
Chicago Midway
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$152
OntarioChicago
ONT Ontario - MDW Chicago Midway
ONTMDW
Ontario
Mon 10/12
11:15 pm-10:03 am
1 stop8h 48m
Chicago Midway
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$157
OntarioChicago
ONT Ontario - MDW Chicago Midway
ONTMDW
Ontario
Fri 10/30
12:16 pm-10:33 pm
1 stop8h 17m
Chicago Midway
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$158
OntarioChicago
ONT Ontario - MDW Chicago Midway
ONTMDW
Ontario
Thu 10/29
12:16 pm-10:33 pm
1 stop8h 17m
Chicago Midway
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$159
OntarioChicago
ONT Ontario - MDW Chicago Midway
ONTMDW
Ontario
Sat 10/10
12:16 pm-10:33 pm
1 stop8h 17m
Chicago Midway
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$159
OntarioChicago
ONT Ontario - MDW Chicago Midway
ONTMDW
Ontario
Tue 12/15
12:20 pm-10:54 pm
1 stop8h 34m
Chicago Midway
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$159
OntarioChicago
ONT Ontario - MDW Chicago Midway
ONTMDW
Ontario
Sat 10/31
12:16 pm-10:33 pm
1 stop8h 17m
Chicago Midway
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$159
OntarioChicago
ONT Ontario - ORD Chicago O'Hare Intl
ONTORD
Ontario
Sun 11/1
6:20 am-4:53 pm
1 stop8h 33m
Chicago O'Hare Intl
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$159
OntarioChicago
ONT Ontario - ORD Chicago O'Hare Intl
ONTORD
Ontario
Tue 10/13
11:56 am-11:34 pm
1 stop9h 38m
Chicago O'Hare Intl
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$159
Showing 1-10 of 59 resultsSorted by cheapest first
Best time to book a flight from Ontario to Illinois
Have a flexible travel schedule? Discover the best time to fly to Illinois from Ontario with our price prediction graph.
ONT-ORD
ONT-MDW
ONT-PIA
ONT-MLI
ONT-CMI
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 Ontario to Illinois
ONT-USIL
ONT-ORD
ONT-MDW
ONT-PIA
ONT-MLI
What is the cheapest month to book a flight from Ontario to Illinois?
Currently, January is the cheapest month in which you can book a flight from Ontario to Illinois (average of $345). Flying from Ontario to Illinois in June is currently the most expensive (average of $482). 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 ONT to IL?
Find hourly flight availability from Ontario 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 October 6, 2026.
Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Ontario to Illinois as you normally would.
Weekly flight availability from Ontario to Illinois
Explore weekly flight availability from Ontario 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 October 6, 2026.
The most flights from ONT to USIL are scheduled on a Monday (1 on average). You will have fewer flight options on Monday, which is when the least amount of flights are scheduled (1 on average).
How much does it cost to fly round-trip from Ontario to Illinois?
Airfare is below average for this route at the moment.
Ontario to Illinois flights typically cost between $314 and $498 in November.The cheapest round-trip price found within the last 5 days was $198 on Frontier (Nov 3-Nov 9).
How far ahead should I book a flight from Ontario to Illinois?
The best time to book flights from Ontario to Illinois is 79 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.
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 October 6, 2026.
Read through reviews of airlines operating flights from Ontario to Illinois, such as Southwest,Delta, andUnited Airlines. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Comfort
8.0
Crew
8.6
Boarding
8.1
Overall
7.9
Food
7.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Comfort
8.0
Crew
8.6
Boarding
8.1
Overall
7.9
Food
7.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Comfort
8.0
Crew
8.6
Boarding
8.1
Overall
7.9
Food
7.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Comfort
8.0
Crew
8.6
Boarding
8.1
Overall
7.9
Food
7.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Comfort
8.0
Crew
8.6
Boarding
8.1
Overall
7.9
Food
7.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Comfort
8.0
Crew
8.6
Boarding
8.1
Overall
7.9
Food
7.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Related info for your journey
Find useful and relevant information for your journey from Ontario to Illinois. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
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Alternative routes for Ontario 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 Ontario to Illinois by cabin class
Find flights from Ontario to Illinois, based on your preferred cabin class, be it economy, premium economy, business, or first class.
Ontario and Illinois flights
Browse other Ontario and Illinois flight options. Last updated on October 6, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
Ontario to Illinois flights
Consider these flights traveling from Ontario to Illinois.
Top 5 airlines flying from Ontario to Illinois
Discover the top 5 airlines that operate flights from Ontario 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 7,457,451 searches. Data last updated October 6, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$131 | Average$296 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$253 | Average$495 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$258 | Average$365 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$274 | Average$447 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$276 | Average$494 | FlexibilityNo cancel fee | On-time71% |