$61+ Cheap flights from Ontario (ONT) 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 9/29. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — ORD
Sep 19 — Sep 261
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
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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 August 20, 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 August 20, 2026.
This Kiwi.com deal was found by Cheapflights users on 8/16. 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 9/146:15 am -
1 stop11h 02m
Mon 9/218:10 pm -
1 stop16h 20m
Deal found 8/16![Frontier logo]()
$140
This Kiwi.com deal was found by Cheapflights users on 8/17. 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 10/76:15 am -
1 stop11h 02m
Wed 10/144:19 pm -
1 stop9h 31m
Deal found 8/17![Frontier logo]()
$141
This Kiwi.com deal was found by Cheapflights users on 8/16. 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 9/96:15 am -
1 stop11h 02m
Fri 9/118:10 pm -
1 stop16h 20m
Deal found 8/16![Frontier logo]()
$159
This Kiwi.com deal was found by Cheapflights users on 8/19. 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 9/96:15 am -
1 stop11h 02m
Wed 9/168:10 pm -
1 stop16h 20m
Deal found 8/19![Frontier logo]()
$160
This Kiwi.com deal was found by Cheapflights users on 8/19. 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.
Sat 9/126:15 am -
1 stop11h 02m
Fri 9/188:10 pm -
1 stop16h 20m
Deal found 8/19![Frontier logo]()
$176
This Kiwi.com deal was found by Cheapflights users on 8/18. 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 9/146:15 am -
1 stop11h 02m
Fri 9/188:10 pm -
1 stop16h 20m
Deal found 8/18![Frontier logo]()
$177
This Kiwi.com deal was found by Cheapflights users on 8/16. 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 9/911:45 am -
2 stops28h 09m
Mon 9/218:10 pm -
1 stop16h 20m
Deal found 8/16![Frontier logo]()
$180
This Kiwi.com deal was found by Cheapflights users on 8/19. 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 10/2811:52 am -
1 stop10h 29m
Mon 11/26:30 am -
2 stops14h 58m
Deal found 8/19![Frontier logo]()
$208
This Booking.com deal was found by Cheapflights users on 8/20. 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.
Fri 9/118:24 pm -
1 stop7h 14m
Mon 9/146:30 am -
1 stop6h 00m
Deal found 8/20![Frontier logo]()
$209
This Booking.com deal was found by Cheapflights users on 8/20. 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.
Thu 8/203:40 pm -
1 stop25h 22m
Sun 8/238:11 pm -
1 stop27h 16m
Deal found 8/20![Frontier logo]()
$210
This Frontier deal was found by Cheapflights users on 8/20. 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 9/68:17 am -
1 stop10h 14m
Thu 9/1012:54 pm -
1 stop7h 45m
Deal found 8/20![Frontier logo]()
$211
This Frontier deal was found by Cheapflights users on 8/20. 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 9/68:17 am -
1 stop9h 58m
Thu 9/101:01 pm -
1 stop7h 38m
Deal found 8/20![Frontier logo]()
$211
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 August 20, 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 August 20, 2026.
This Southwest deal was found by Cheapflights users on 8/18. 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.
Sat 10/2411:50 am -
1 stop6h 05m
Wed 10/284:45 pm -
1 stop6h 00m
Deal found 8/18![Southwest logo]()
$254
This Kiwi.com deal was found by Cheapflights users on 8/15. 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.
Thu 9/108:00 am -
1 stop10h 39m
Sun 9/139:29 pm -
1 stop11h 35m
Deal found 8/15![Multiple Airlines logo]()
$267
This Delta deal was found by Cheapflights users on 8/19. 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 1/1912:00 pm -
1 stop9h 50m
Sun 1/315:30 am -
1 stop7h 57m
Deal found 8/19![Delta logo]()
$268
This United Airlines deal was found by Cheapflights users on 8/19. 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 10/11:24 pm -
1 stop8h 35m
Mon 10/58:20 pm -
Nonstop4h 29m
Deal found 8/19![United Airlines logo]()
$336
This Alaska Airlines deal was found by Cheapflights users on 8/19. 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 9/1512:12 pm -
1 stop9h 47m
Thu 9/246:00 am -
1 stop10h 16m
Deal found 8/19![Alaska Airlines logo]()
$348
This American Airlines deal was found by Cheapflights users on 8/20. 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 10/141:05 pm -
2 stops8h 37m
Wed 10/218:03 am -
1 stop6h 11m
Deal found 8/20![American Airlines logo]()
$362
This Southwest deal was found by Cheapflights users on 8/20. 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.
Sat 9/194:00 pm -
1 stop11h 55m
Sat 9/265:05 pm -
1 stop5h 50m
Deal found 8/20![Southwest logo]()
$264
This Delta deal was found by Cheapflights users on 8/20. 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 10/296:01 pm -
2 stops12h 43m
Fri 11/61:27 pm -
2 stops11h 16m
Deal found 8/20![Delta logo]()
$278
This Kiwi.com deal was found by Cheapflights users on 8/19. 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.
Thu 9/248:00 am -
1 stop10h 39m
Sun 9/279:29 pm -
1 stop11h 35m
Deal found 8/19![Multiple Airlines logo]()
$294
This Southwest deal was found by Cheapflights users on 8/19. 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.
Sat 8/2911:55 pm -
Nonstop3h 50m
Sun 8/3010:40 am -
2 stops7h 20m
Deal found 8/19![Southwest logo]()
$272
This Delta deal was found by Cheapflights users on 8/19. 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 9/412:00 pm -
1 stop9h 57m
Tue 9/812:29 pm -
2 stops11h 35m
Deal found 8/19![Delta logo]()
$282
This Southwest deal was found by Cheapflights users on 8/19. 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 11/24:00 pm -
2 stops7h 05m
Fri 11/612:45 pm -
2 stops9h 05m
Deal found 8/19![Southwest logo]()
$278
This United Airlines deal was found by Cheapflights users on 8/15. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/117:00 am -
Nonstop4h 10m
Wed 11/184:15 pm -
Nonstop4h 32m
Deal found 8/15![United Airlines logo]()
$342
This American Airlines deal was found by Cheapflights users on 8/16. 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 12/22:22 pm -
1 stop6h 55m
Thu 12/102:34 pm -
2 stops9h 19m
Deal found 8/16![American Airlines logo]()
$364
This Alaska Airlines deal was found by Cheapflights users on 8/20. 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 9/227:12 am -
1 stop7h 58m
Thu 10/13:09 pm -
1 stop10h 15m
Deal found 8/20![Alaska Airlines logo]()
$367
This Southwest deal was found by Cheapflights users on 8/19. 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 8/2811:00 am -
1 stop7h 10m
Sat 8/295:40 am -
1 stop11h 35m
Deal found 8/19![Southwest logo]()
$282
This Kiwi.com deal was found by Cheapflights users on 8/19. 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.
Thu 9/248:00 am -
1 stop10h 39m
Thu 10/19:03 pm -
1 stop12h 01m
Deal found 8/19![Multiple Airlines logo]()
$348
This United Airlines deal was found by Cheapflights users on 8/16. 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 9/51:18 pm -
1 stop5h 43m
Wed 9/910:42 am -
2 stops11h 19m
Deal found 8/16![United Airlines logo]()
$355
This Delta deal was found by Cheapflights users on 8/16. 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 9/21:06 pm -
1 stop6h 27m
Sun 9/66:00 am -
2 stops8h 16m
Deal found 8/16![Delta logo]()
$334
This Alaska Airlines deal was found by Cheapflights users on 8/16. 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 10/222:13 pm -
1 stop7h 46m
Mon 10/267:02 am -
1 stop8h 14m
Deal found 8/16![Alaska Airlines logo]()
$377
This Southwest deal was found by Cheapflights users on 8/15. 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.
Tue 8/256:40 am -
2 stops8h 30m
Wed 9/210:30 am -
2 stops7h 35m
Deal found 8/15![Southwest logo]()
$287
This American Airlines deal was found by Cheapflights users on 8/15. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/231:04 pm -
2 stops9h 23m
Wed 9/308:00 am -
1 stop6h 06m
Deal found 8/15![American Airlines logo]()
$382
This United Airlines deal was found by Cheapflights users on 8/16. 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.
Wed 11/187:00 am -
Nonstop4h 10m
Sun 11/226:00 am -
1 stop8h 29m
Deal found 8/16![United Airlines logo]()
$358
This Kiwi.com deal was found by Cheapflights users on 8/18. 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.
Thu 9/178:00 am -
1 stop10h 39m
Sun 9/209:29 pm -
1 stop21h 30m
Deal found 8/18![Multiple Airlines logo]()
$363
This Southwest deal was found by Cheapflights users on 8/20. 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.
Sat 9/2611:55 pm -
Nonstop3h 50m
Wed 9/305:25 pm -
Nonstop4h 15m
Deal found 8/20![Southwest logo]()
$293
This Delta deal was found by Cheapflights users on 8/20. 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 9/2410:00 pm -
1 stop9h 00m
Wed 9/306:55 pm -
1 stop6h 52m
Deal found 8/20![Delta logo]()
$357
This United Airlines deal was found by Cheapflights users on 8/15. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/161:56 pm -
1 stop7h 09m
Sun 9/205:00 am -
1 stop9h 12m
Deal found 8/15![United Airlines logo]()
$368
This Kiwi.com deal was found by Cheapflights users on 8/18. 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.
Thu 10/2911:19 am -
1 stop6h 11m
Thu 11/58:52 pm -
1 stop15h 32m
Deal found 8/18![Multiple Airlines logo]()
$380
This Southwest deal was found by Cheapflights users on 8/17. 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 9/911:55 pm -
Nonstop3h 50m
Thu 9/102:00 pm -
Nonstop4h 10m
Deal found 8/17![Southwest logo]()
$293
This American Airlines deal was found by Cheapflights users on 8/16. 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 9/26:00 am -
1 stop8h 02m
Sat 9/511:32 am -
2 stops8h 43m
Deal found 8/16![American Airlines logo]()
$434
Last-minute flights from Ontario to IllinoisDiscover last-minute flight deals from Ontario to Illinois. Data last updated August 20, 2026 and is based on user searches.
Discover last-minute flight deals from Ontario to Illinois. Data last updated August 20, 2026 and is based on user searches.
This Booking.com deal was found by Cheapflights users on 8/20. 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.
Thu 8/203:40 pm -
1 stop25h 22m
Sun 8/238:11 pm -
1 stop27h 16m
Deal found 8/20![Frontier logo]()
$210
This Frontier deal was found by Cheapflights users on 8/20. 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 9/68:17 am -
1 stop10h 14m
Thu 9/1012:54 pm -
1 stop7h 45m
Deal found 8/20![Frontier logo]()
$211
This Frontier deal was found by Cheapflights users on 8/20. 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 9/68:17 am -
1 stop9h 58m
Thu 9/101:01 pm -
1 stop7h 38m
Deal found 8/20![Frontier logo]()
$211
This Kiwi.com deal was found by Cheapflights users on 8/16. 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 9/96:15 am -
1 stop11h 02m
Fri 9/118:10 pm -
1 stop16h 20m
Deal found 8/16![Frontier logo]()
$159
This Kiwi.com deal was found by Cheapflights users on 8/19. 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 9/96:15 am -
1 stop11h 02m
Wed 9/168:10 pm -
1 stop16h 20m
Deal found 8/19![Frontier logo]()
$160
This Kiwi.com deal was found by Cheapflights users on 8/16. 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 9/911:45 am -
2 stops28h 09m
Mon 9/218:10 pm -
1 stop16h 20m
Deal found 8/16![Frontier logo]()
$180
This Booking.com deal was found by Cheapflights users on 8/20. 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.
Fri 9/118:24 pm -
1 stop7h 14m
Mon 9/146:30 am -
1 stop6h 00m
Deal found 8/20![Frontier logo]()
$209
This Kiwi.com deal was found by Cheapflights users on 8/19. 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.
Sat 9/126:15 am -
1 stop11h 02m
Fri 9/188:10 pm -
1 stop16h 20m
Deal found 8/19![Frontier logo]()
$176
This Kiwi.com deal was found by Cheapflights users on 8/16. 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 9/146:15 am -
1 stop11h 02m
Mon 9/218:10 pm -
1 stop16h 20m
Deal found 8/16![Frontier logo]()
$140
This Kiwi.com deal was found by Cheapflights users on 8/18. 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 9/146:15 am -
1 stop11h 02m
Fri 9/188:10 pm -
1 stop16h 20m
Deal found 8/18![Frontier logo]()
$177
This Trip.com deal was found by Cheapflights users on 8/20. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/248:24 pm -
1 stop7h 14m
Sun 9/276:30 am -
1 stop6h 00m
Deal found 8/20![Frontier logo]()
$212
This Kiwi.com deal was found by Cheapflights users on 8/20. 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.
Thu 9/248:24 pm -
1 stop7h 14m
Tue 9/297:28 pm -
2 stops30h 19m
Deal found 8/20![Frontier logo]()
$213
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 August 20, 2026.
Search for one-way flight options from Ontario to Illinois. Find affordable one-way fares based on user searches. Data last updated August 20, 2026.
This Trip.com deal was found by Cheapflights users on 8/17. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/2911:45 am -
1 stop10h 38m
Deal found 8/17![Frontier logo]()
$61
This Trip.com deal was found by Cheapflights users on 8/15. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/1411:45 am -
1 stop10h 38m
Deal found 8/15![Frontier logo]()
$64
This Trip.com deal was found by Cheapflights users on 8/15. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/2011:52 am -
1 stop10h 32m
Deal found 8/15![Frontier logo]()
$65
This Super.com deal was found by Cheapflights users on 8/15. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/108:24 pm -
1 stop7h 14m
Deal found 8/15![Frontier logo]()
$79
This Frontier deal was found by Cheapflights users on 8/16. 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 10/18:24 pm -
1 stop7h 14m
Deal found 8/16![Frontier logo]()
$80
This Frontier deal was found by Cheapflights users on 8/17. 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 10/88:35 pm -
1 stop6h 41m
Deal found 8/17![Frontier logo]()
$82
This Super.com deal was found by Cheapflights users on 8/17. 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.
Sat 9/122:30 pm -
1 stop13h 08m
Deal found 8/17![Frontier logo]()
$84
This Super.com deal was found by Cheapflights users on 8/17. 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.
Wed 9/96:15 am -
1 stop16h 08m
Deal found 8/17![Frontier logo]()
$85
This Frontier deal was found by Cheapflights users on 8/16. 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.
Wed 10/711:45 am -
1 stop10h 38m
Deal found 8/16![Frontier logo]()
$86
This Frontier deal was found by Cheapflights users on 8/17. 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 10/511:45 am -
1 stop10h 38m
Deal found 8/17![Frontier logo]()
$87
This Super.com deal was found by Cheapflights users on 8/17. 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.
Tue 9/19:37 am -
1 stop8h 38m
Deal found 8/17![Frontier logo]()
$88
This Super.com deal was found by Cheapflights users on 8/17. 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.
Sun 8/308:17 am -
1 stop10h 14m
Deal found 8/17![Frontier logo]()
$93
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 August 20, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $140 (Kiwi.com) |
One-way from | $61 (Trip.com) |
Popular in | June |
Cheapest in | September |
Average price | $354 |
Good round-trip deal | $377 or less |
Good one-way deal | $193 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 August 20, 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
Sat 10/24
11:50 am-7:55 pm
1 stop6h 05m
Chicago Midway
Wed 10/28
4:45 pm-8:45 pm
1 stop6h 00m
$254
OntarioChicago
ONT Ontario - MDW Chicago Midway
ONTMDW
Ontario
Sat 9/19
4:00 pm-5:55 am
1 stop11h 55m
Chicago Midway
Sat 9/26
5:05 pm-8:55 pm
1 stop5h 50m
$264
OntarioChicago
ONT Ontario - RFD Chicago Greater Rockford
ONTRFD
Ontario
Thu 9/10
8:00 am-8:39 pm
1 stop10h 39m
Chicago Greater Rockford
Sun 9/13
9:29 pm-7:04 am
1 stop11h 35m
$267
OntarioChicago
ONT Ontario - ORD Chicago O'Hare Intl
ONTORD
Ontario
Tue 1/19
12:00 pm-11:50 pm
1 stop9h 50m
Chicago O'Hare Intl
Sun 1/31
5:30 am-11:27 am
1 stop7h 57m
$268
OntarioChicago
ONT Ontario - MDW Chicago Midway
ONTMDW
Ontario
Sat 8/29
11:55 pm-5:45 am
Nonstop3h 50m
Chicago Midway
Sun 8/30
10:40 am-4:00 pm
2 stops7h 20m
$272
OntarioChicago
ONT Ontario - MDW Chicago Midway
ONTMDW
Ontario
Thu 10/29
6:01 pm-8:44 am
2 stops12h 43m
Chicago Midway
Fri 11/6
1:27 pm-10:43 pm
2 stops11h 16m
$278
OntarioChicago
ONT Ontario - MDW Chicago Midway
ONTMDW
Ontario
Mon 11/2
4:00 pm-1:05 am
2 stops7h 05m
Chicago Midway
Fri 11/6
12:45 pm-7:50 pm
2 stops9h 05m
$278
OntarioChicago
ONT Ontario - ORD Chicago O'Hare Intl
ONTORD
Ontario
Fri 9/4
12:00 pm-11:57 pm
1 stop9h 57m
Chicago O'Hare Intl
Tue 9/8
12:29 pm-10:04 pm
2 stops11h 35m
$282
OntarioChicago
ONT Ontario - MDW Chicago Midway
ONTMDW
Ontario
Fri 8/28
11:00 am-8:10 pm
1 stop7h 10m
Chicago Midway
Sat 8/29
5:40 am-3:15 pm
1 stop11h 35m
$282
OntarioChicago
ONT Ontario - MDW Chicago Midway
ONTMDW
Ontario
Tue 8/25
6:40 am-5:10 pm
2 stops8h 30m
Chicago Midway
Wed 9/2
10:30 am-4:05 pm
2 stops7h 35m
$287
Showing 1-10 of 60 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-MDW
ONT-RFD
ONT-ORD
ONT-STL
ONT-BMI
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-MDW
ONT-RFD
ONT-ORD
ONT-STL
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 August 20, 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 August 20, 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 $307 and $538 in October.The cheapest round-trip price found within the last 5 days was $208 on Frontier (Oct 28-Nov 2).
How far ahead should I book a flight from Ontario to Illinois?
The best time to book flights from Ontario to Illinois is 75 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 August 20, 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.
Food
7.0
Entertainment
7.5
Boarding
8.1
Comfort
8.0
Crew
8.6
Overall
8.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Entertainment
7.5
Boarding
8.1
Comfort
8.0
Crew
8.6
Overall
8.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Entertainment
7.5
Boarding
8.1
Comfort
8.0
Crew
8.6
Overall
8.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Entertainment
7.5
Boarding
8.1
Comfort
8.0
Crew
8.6
Overall
8.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Entertainment
7.5
Boarding
8.1
Comfort
8.0
Crew
8.6
Overall
8.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Entertainment
7.5
Boarding
8.1
Comfort
8.0
Crew
8.6
Overall
8.0
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 August 20, 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 August 20, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$131 | Average$258 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$255 | Average$427 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$258 | Average$446 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$269 | Average$455 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$288 | Average$445 | FlexibilityNo cancel fee | On-time71% |