$87+ 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 9/11. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — ORD
Sep 9 — Sep 161
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 10, 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 10, 2026.
This Kiwi.com deal was found by Cheapflights users on 8/7. 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 9/116:15 am -
1 stop11h 02m
Mon 9/148:10 pm -
1 stop5h 37m
Deal found 8/7![Frontier logo]()
$222
This Frontier deal was found by Cheapflights users on 8/5. 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.
Wed 9/1611:45 am -
1 stop5h 32m
Sat 9/2612:17 pm -
1 stop6h 17m
Deal found 8/5![Frontier logo]()
$252
This Frontier deal was found by Cheapflights users on 8/7. 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.
Sat 8/297:56 pm -
1 stop21h 17m
Sat 9/56:45 pm -
1 stop15h 18m
Deal found 8/7![Frontier logo]()
$253
This Kiwi.com deal was found by Cheapflights users on 8/6. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/229:12 pm -
2 stops10h 28m
Thu 10/298:10 pm -
1 stop29h 45m
Deal found 8/6![Frontier logo]()
$254
This Booking.com deal was found by Cheapflights users on 8/7. 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 9/225:44 pm -
1 stop15h 48m
Tue 9/2912:17 pm -
1 stop6h 42m
Deal found 8/7![Frontier logo]()
$258
This CheapOair deal was found by Cheapflights users on 8/7. 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 9/83:40 pm -
1 stop17h 52m
Thu 9/1010:20 am -
1 stop10h 19m
Deal found 8/7![Frontier logo]()
$262
This Booking.com deal was found by Cheapflights users on 8/7. 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 9/295:44 pm -
1 stop15h 48m
Thu 10/110:20 am -
1 stop10h 19m
Deal found 8/7![Frontier logo]()
$264
This Kiwi.com deal was found by Cheapflights users on 8/9. 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 10/248:07 am -
2 stops23h 33m
Thu 10/298:10 pm -
1 stop29h 45m
Deal found 8/9![Frontier logo]()
$265
This Southwest deal was found by Cheapflights users on 8/9. 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 11/111:30 pm -
1 stop7h 35m
Tue 12/15:05 am -
1 stop6h 40m
Deal found 8/9![Southwest logo]()
$268
This United Airlines deal was found by Cheapflights users on 8/10. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/101:50 pm -
1 stop9h 09m
Wed 8/125:55 am -
1 stop8h 55m
Deal found 8/10![United Airlines logo]()
$272
This Kiwi.com deal was found by Cheapflights users on 8/9. 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 8/289:33 am -
1 stop13h 16m
Tue 9/11:59 pm -
2 stops31h 02m
Deal found 8/9![Frontier logo]()
$274
This Southwest deal was found by Cheapflights users on 8/10. 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.
Wed 9/212:30 pm -
1 stop8h 40m
Sat 9/56:00 pm -
Nonstop4h 15m
Deal found 8/10![Southwest logo]()
$275
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 10, 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 10, 2026.
This Frontier deal was found by Cheapflights users on 8/5. 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.
Mon 10/192:58 pm -
1 stop8h 19m
Fri 10/238:10 pm -
1 stop5h 45m
Deal found 8/5![Frontier logo]()
$266
This Southwest deal was found by Cheapflights users on 8/8. 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 8/282:00 pm -
1 stop7h 45m
Sat 8/291:15 pm -
1 stop7h 05m
Deal found 8/8![Southwest logo]()
$277
This Delta deal was found by Cheapflights users on 8/7. 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.
Mon 8/2410:00 pm -
2 stops10h 42m
Wed 8/267:44 pm -
1 stop5h 50m
Deal found 8/7![Delta logo]()
$282
This Kiwi.com deal was found by Cheapflights users on 8/7. 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.
Tue 11/104:27 pm -
2 stops17h 56m
Sun 11/158:37 pm -
1 stop15h 47m
Deal found 8/7![Multiple Airlines logo]()
$286
This United Airlines deal was found by Cheapflights users on 8/9. 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 9/207:00 am -
Nonstop4h 10m
Sat 9/262:30 pm -
1 stop8h 28m
Deal found 8/9![United Airlines logo]()
$312
This Alaska Airlines deal was found by Cheapflights users on 8/6. 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 9/246:02 am -
1 stop10h 36m
Sat 9/266:29 am -
1 stop9h 47m
Deal found 8/6![Alaska Airlines logo]()
$391
This American Airlines deal was found by Cheapflights users on 8/10. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/257:05 am -
1 stop7h 14m
Sat 8/294:49 pm -
1 stop8h 10m
Deal found 8/10![American Airlines logo]()
$429
This Southwest deal was found by Cheapflights users on 8/10. 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 9/1811:55 pm -
Nonstop3h 50m
Tue 9/225:25 pm -
Nonstop4h 15m
Deal found 8/10![Southwest logo]()
$280
This Delta deal was found by Cheapflights users on 8/7. 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 10/136:01 pm -
2 stops11h 40m
Sun 10/185:27 am -
1 stop7h 39m
Deal found 8/7![Delta logo]()
$282
This Kiwi.com deal was found by Cheapflights users on 8/7. 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 11/1211:19 am -
1 stop6h 43m
Sun 11/158:37 pm -
1 stop15h 47m
Deal found 8/7![Multiple Airlines logo]()
$303
This Southwest deal was found by Cheapflights users on 8/7. 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 8/2112:50 pm -
2 stops8h 30m
Tue 8/2510:30 am -
2 stops7h 35m
Deal found 8/7![Southwest logo]()
$287
This Delta deal was found by Cheapflights users on 8/10. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/166:01 pm -
2 stops12h 52m
Tue 10/202:03 pm -
2 stops10h 40m
Deal found 8/10![Delta logo]()
$288
This Booking.com deal was found by Cheapflights users on 8/5. 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.
Thu 9/33:40 pm -
1 stop24h 10m
Fri 9/47:58 pm -
1 stop5h 52m
Deal found 8/5![Frontier logo]()
$323
This Kiwi.com deal was found by Cheapflights users on 8/5. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/511:19 am -
1 stop6h 43m
Sun 11/88:37 pm -
1 stop26h 11m
Deal found 8/5![Multiple Airlines logo]()
$318
This United Airlines deal was found by Cheapflights users on 8/8. 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 10/177:00 am -
Nonstop4h 10m
Sun 10/186:07 am -
1 stop8h 11m
Deal found 8/8![United Airlines logo]()
$367
This Kiwi.com deal was found by Cheapflights users on 8/9. 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 8/9![Multiple Airlines logo]()
$319
This Southwest deal was found by Cheapflights users on 8/9. 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 8/252:10 pm -
1 stop6h 35m
Wed 9/98:35 am -
1 stop5h 55m
Deal found 8/9![Southwest logo]()
$322
This United Airlines deal was found by Cheapflights users on 8/7. 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 8/269:01 am -
1 stop9h 39m
Mon 8/314:11 pm -
1 stop7h 48m
Deal found 8/7![United Airlines logo]()
$377
This Kiwi.com deal was found by Cheapflights users on 8/7. 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.
Tue 9/83:40 pm -
2 stops19h 39m
Sun 9/139:29 pm -
1 stop11h 35m
Deal found 8/7![Multiple Airlines logo]()
$323
This American Airlines deal was found by Cheapflights users on 8/7. 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 8/222:43 pm -
1 stop6h 10m
Wed 8/265:00 am -
2 stops9h 03m
Deal found 8/7![American Airlines logo]()
$434
This Southwest deal was found by Cheapflights users on 8/6. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/66:55 am -
2 stops7h 30m
Wed 9/910:30 am -
2 stops7h 35m
Deal found 8/6![Southwest logo]()
$328
This United Airlines deal was found by Cheapflights users on 8/9. 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 8/221:18 pm -
1 stop8h 41m
Sat 8/292:35 pm -
1 stop7h 26m
Deal found 8/9![United Airlines logo]()
$377
This Delta deal was found by Cheapflights users on 8/9. 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 8/286:01 pm -
2 stops12h 29m
Sun 8/305:30 am -
1 stop7h 12m
Deal found 8/9![Delta logo]()
$382
This Southwest deal was found by Cheapflights users on 8/10. 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 9/1811:55 pm -
Nonstop3h 50m
Mon 9/212:00 pm -
Nonstop4h 10m
Deal found 8/10![Southwest logo]()
$335
This United Airlines deal was found by Cheapflights users on 8/6. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/279:01 am -
1 stop9h 25m
Mon 8/318:06 pm -
Nonstop4h 29m
Deal found 8/6![United Airlines logo]()
$379
This Delta deal was found by Cheapflights users on 8/6. 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 8/2812:00 pm -
1 stop9h 16m
Mon 8/3112:09 pm -
1 stop9h 44m
Deal found 8/6![Delta logo]()
$390
This American Airlines deal was found by Cheapflights users on 8/9. 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 12/57:00 am -
1 stop8h 28m
Sat 12/127:00 am -
1 stop6h 52m
Deal found 8/9![American Airlines logo]()
$481
This Kiwi.com deal was found by Cheapflights users on 8/9. 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 8/2711:15 am -
1 stop7h 30m
Sun 8/309:35 pm -
1 stop12h 28m
Deal found 8/9![Multiple Airlines logo]()
$373
This United Airlines deal was found by Cheapflights users on 8/5. 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 10/101:52 pm -
1 stop7h 06m
Sat 10/178:20 pm -
Nonstop4h 29m
Deal found 8/5![United Airlines logo]()
$379
This Delta deal was found by Cheapflights users on 8/7. 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 11/116:00 am -
1 stop5h 30m
Tue 11/176:00 am -
1 stop7h 10m
Deal found 8/7![Delta logo]()
$391
Last-minute flights from Ontario to IllinoisDiscover last-minute flight deals from Ontario to Illinois. Data last updated August 10, 2026 and is based on user searches.
Discover last-minute flight deals from Ontario to Illinois. Data last updated August 10, 2026 and is based on user searches.
This Delta deal was found by Cheapflights users on 8/6. 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.
Wed 8/199:43 am -
1 stop6h 36m
Sun 8/235:30 am -
1 stop7h 12m
Deal found 8/6![Delta logo]()
$277
This Southwest deal was found by Cheapflights users on 8/7. 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 8/246:45 pm -
1 stop8h 15m
Wed 8/266:50 am -
1 stop7h 50m
Deal found 8/7![Southwest logo]()
$277
This Delta deal was found by Cheapflights users on 8/8. 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.
Mon 8/2412:00 pm -
1 stop8h 36m
Fri 8/2812:46 pm -
1 stop7h 44m
Deal found 8/8![Delta logo]()
$278
This Frontier deal was found by Cheapflights users on 8/7. 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.
Sat 8/297:56 pm -
1 stop21h 17m
Sat 9/56:45 pm -
1 stop15h 18m
Deal found 8/7![Frontier logo]()
$253
This Southwest deal was found by Cheapflights users on 8/10. 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.
Wed 9/212:30 pm -
1 stop8h 40m
Sat 9/56:00 pm -
Nonstop4h 15m
Deal found 8/10![Southwest logo]()
$275
This CheapOair deal was found by Cheapflights users on 8/7. 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 9/83:40 pm -
1 stop17h 52m
Thu 9/1010:20 am -
1 stop10h 19m
Deal found 8/7![Frontier logo]()
$262
This Kiwi.com deal was found by Cheapflights users on 8/7. 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 9/116:15 am -
1 stop11h 02m
Mon 9/148:10 pm -
1 stop5h 37m
Deal found 8/7![Frontier logo]()
$222
This Frontier deal was found by Cheapflights users on 8/7. 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 9/1611:45 am -
1 stop5h 32m
Sat 9/2612:17 pm -
1 stop6h 17m
Deal found 8/7![Frontier logo]()
$252
This Booking.com deal was found by Cheapflights users on 8/7. 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 9/182:30 pm -
1 stop19h 02m
Mon 9/218:10 pm -
1 stop5h 37m
Deal found 8/7![Frontier logo]()
$272
This Booking.com deal was found by Cheapflights users on 8/7. 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 9/225:44 pm -
1 stop15h 48m
Tue 9/2912:17 pm -
1 stop6h 42m
Deal found 8/7![Frontier logo]()
$258
This Southwest deal was found by Cheapflights users on 8/9. 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 am -
1 stop5h 55m
Wed 10/72:25 pm -
1 stop6h 10m
Deal found 8/9![Southwest logo]()
$268
This Booking.com deal was found by Cheapflights users on 8/7. 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 9/295:44 pm -
1 stop15h 48m
Thu 10/110:20 am -
1 stop10h 19m
Deal found 8/7![Frontier logo]()
$264
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 10, 2026.
Search for one-way flight options from Ontario to Illinois. Find affordable one-way fares based on user searches. Data last updated August 10, 2026.
This Super.com deal was found by Cheapflights users on 8/7. 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 9/118:24 pm -
1 stop7h 14m
Deal found 8/7![Frontier logo]()
$87
This Super.com deal was found by Cheapflights users on 8/7. 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 8/189:37 am -
1 stop8h 38m
Deal found 8/7![Frontier logo]()
$88
This Frontier deal was found by Cheapflights users on 8/6. 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 9/68:17 am -
1 stop9h 58m
Deal found 8/6![Frontier logo]()
$89
This Mytrip deal was found by Cheapflights users on 8/6. 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.
Tue 9/19:37 am -
1 stop8h 38m
Deal found 8/6![Frontier logo]()
$90
This Super.com deal was found by Cheapflights users on 8/10. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/289:33 am -
1 stop13h 16m
Deal found 8/10![Frontier logo]()
$92
This Super.com deal was found by Cheapflights users on 8/7. 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 8/7![Frontier logo]()
$93
This Super.com deal was found by Cheapflights users on 8/9. 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 8/219:33 am -
1 stop13h 16m
Deal found 8/9![Frontier logo]()
$93
This Super.com deal was found by Cheapflights users on 8/6. 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.
Sun 9/68:17 am -
1 stop10h 14m
Deal found 8/6![Frontier logo]()
$94
This Super.com deal was found by Cheapflights users on 8/10. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/179:36 am -
1 stop28h 23m
Deal found 8/10![Frontier logo]()
$94
This Expedia deal was found by Cheapflights users on 8/6. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/65:44 pm -
1 stop9h 54m
Deal found 8/6![Frontier logo]()
$95
This Mytrip deal was found by Cheapflights users on 8/9. 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.
Sun 8/169:36 am -
1 stop12h 57m
Deal found 8/9![Frontier logo]()
$96
This Trip.com deal was found by Cheapflights users on 8/7. 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 8/318:17 am -
1 stop10h 14m
Deal found 8/7![Frontier logo]()
$98
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 10, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $222 (Kiwi.com) |
One-way from | $87 (Super.com) |
Popular in | June |
Cheapest in | September |
Average price | $334 |
Good round-trip deal | $380 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 2,558,603 searches. Data last updated August 10, 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
OntarioSt. Louis
ONT Ontario - STL Lambert-St Louis
ONTSTL
Ontario
Mon 10/19
2:58 pm-1:17 am
1 stop8h 19m
Lambert-St Louis
Fri 10/23
8:10 pm-11:55 pm
1 stop5h 45m
$266
OntarioChicago
ONT Ontario - MDW Chicago Midway
ONTMDW
Ontario
Fri 8/28
2:00 pm-11:45 pm
1 stop7h 45m
Chicago Midway
Sat 8/29
1:15 pm-6:20 pm
1 stop7h 05m
$277
OntarioChicago
ONT Ontario - MDW Chicago Midway
ONTMDW
Ontario
Fri 9/18
11:55 pm-5:45 am
Nonstop3h 50m
Chicago Midway
Tue 9/22
5:25 pm-7:40 pm
Nonstop4h 15m
$280
OntarioChicago
ONT Ontario - ORD Chicago O'Hare Intl
ONTORD
Ontario
Mon 8/24
10:00 pm-10:42 am
2 stops10h 42m
Chicago O'Hare Intl
Wed 8/26
7:44 pm-11:34 pm
1 stop5h 50m
$282
OntarioChicago
ONT Ontario - ORD Chicago O'Hare Intl
ONTORD
Ontario
Tue 10/13
6:01 pm-7:41 am
2 stops11h 40m
Chicago O'Hare Intl
Sun 10/18
5:27 am-11:06 am
1 stop7h 39m
$282
OntarioChicago
ONT Ontario - RFD Chicago Greater Rockford
ONTRFD
Ontario
Tue 11/10
4:27 pm-12:23 pm
2 stops17h 56m
Chicago Greater Rockford
Sun 11/15
8:37 pm-10:24 am
1 stop15h 47m
$286
OntarioChicago
ONT Ontario - MDW Chicago Midway
ONTMDW
Ontario
Fri 8/21
12:50 pm-11:20 pm
2 stops8h 30m
Chicago Midway
Tue 8/25
10:30 am-4:05 pm
2 stops7h 35m
$287
OntarioChicago
ONT Ontario - ORD Chicago O'Hare Intl
ONTORD
Ontario
Fri 10/16
6:01 pm-8:53 am
2 stops12h 52m
Chicago O'Hare Intl
Tue 10/20
2:03 pm-10:43 pm
2 stops10h 40m
$288
OntarioChicago
ONT Ontario - RFD Chicago Greater Rockford
ONTRFD
Ontario
Thu 11/12
11:19 am-8:02 pm
1 stop6h 43m
Chicago Greater Rockford
Sun 11/15
8:37 pm-10:24 am
1 stop15h 47m
$303
OntarioChicago
ONT Ontario - ORD Chicago O'Hare Intl
ONTORD
Ontario
Sun 9/20
7:00 am-1:10 pm
Nonstop4h 10m
Chicago O'Hare Intl
Sat 9/26
2:30 pm-8:58 pm
1 stop8h 28m
$312
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-ORD
ONT-MDW
ONT-STL
ONT-RFD
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-ORD
ONT-MDW
ONT-STL
ONT-RFD
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 10, 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.
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 $343 and $497 in August.The cheapest round-trip price found within the last 5 days was $274 on Frontier (Aug 28-Sep 1).
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 10, 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.
Boarding
8.1
Overall
8.0
Entertainment
7.5
Crew
8.6
Food
7.0
Comfort
8.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Boarding
8.1
Overall
8.0
Entertainment
7.5
Crew
8.6
Food
7.0
Comfort
8.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Boarding
8.1
Overall
8.0
Entertainment
7.5
Crew
8.6
Food
7.0
Comfort
8.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Boarding
8.1
Overall
8.0
Entertainment
7.5
Crew
8.6
Food
7.0
Comfort
8.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Boarding
8.1
Overall
8.0
Entertainment
7.5
Crew
8.6
Food
7.0
Comfort
8.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Boarding
8.1
Overall
8.0
Entertainment
7.5
Crew
8.6
Food
7.0
Comfort
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 10, 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 2,558,603 searches. Data last updated August 10, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$131 | Average$266 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$255 | Average$428 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$258 | Average$446 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$268 | Average$458 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$294 | Average$472 | FlexibilityNo cancel fee | On-time71% |