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$54+ 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 2/23. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — ORD
dic. 24 — dic. 311
mar. 12/24
mar. 12/31
1 adult, Economy
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Cheap flight deals from Ontario to Illinois

Discover tips and strategies to find the most affordable flight options for your journey from Ontario (ONT) to Illinois (USIL). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated diciembre 19, 2024.

Round-trip from

$106
(Cheapflightsfares)

One-way from

$54
(Cheapflightsfares)
From Ontario to Illinois
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One-way flight from Ontario to Illinois
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Find flight deals from Ontario to Illinois

Cheapest flights from Ontario to Illinois
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 diciembre 19, 2024.

This Booking.com deal was found by Cheapflights users on 12/17. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 12/3112:59 amONT - STL
1 stop5h 14mFrontier
vie. 1/39:29 pmSTL - ONT
1 stop22h 41mFrontier
Deal found 12/17$158
This CheapOair deal was found by Cheapflights users on 12/17. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 12/3112:59 amONT - MDW
1 stop18h 33mFrontier
dom. 1/58:41 pmMDW - ONT
1 stop12h 28mFrontier
Deal found 12/17$168
This Frontier deal was found by Cheapflights users on 12/18. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
lun. 12/3012:59 amONT - ORD
1 stop10h 21mFrontier
lun. 1/137:50 amORD - ONT
1 stop11h 45mFrontier
Deal found 12/18$208
This Delta deal was found by Cheapflights users on 12/17. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 12/241:05 pmONT - STL
1 stop6h 29mDelta
mar. 1/215:00 pmSTL - ONT
1 stop7h 52mDelta
Deal found 12/17$336
This American Airlines deal was found by Cheapflights users on 12/18. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 12/3111:59 pmONT - ORD
1 stop9h 04mAmerican Airlines
mar. 1/74:55 pmORD - ONT
1 stop7h 50mAmerican Airlines
Deal found 12/18$410
This United Airlines deal was found by Cheapflights users on 12/17. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 12/246:10 amONT - STL
1 stop8h 37mUnited Airlines
mar. 1/214:36 pmSTL - ONT
2 stops19h 15mUnited Airlines
Deal found 12/17$440
This Delta deal was found by Cheapflights users on 12/17. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 12/315:30 amONT - MDW
2 stops9h 41mDelta
lun. 1/65:07 pmMDW - ONT
1 stop7h 45mDelta
Deal found 12/17$447
This Delta deal was found by Cheapflights users on 12/18. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mié. 12/255:30 amONT - ORD
1 stop6h 21mDelta
vie. 1/37:30 amORD - ONT
1 stop6h 50mDelta
Deal found 12/18$464
This Delta deal was found by Cheapflights users on 12/18. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 12/1911:56 amONT - MLI
1 stop8h 28mDelta
lun. 12/234:59 pmMLI - ONT
1 stop8h 42mDelta
Deal found 12/18$488
This Alaska Airlines deal was found by Cheapflights users on 12/17. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 12/268:32 pmONT - ORD
1 stop6h 58mAlaska Airlines
mié. 1/86:55 pmORD - ONT
1 stop29h 18mAlaska Airlines
Deal found 12/17$490
This Southwest deal was found by Cheapflights users on 12/17. 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.
mar. 12/312:50 pmONT - MDW
1 stop6h 35mSouthwest
lun. 1/610:00 amMDW - ONT
Nonstop4h 25mSouthwest
Deal found 12/17$498
This United deal was found by Cheapflights users on 12/18. 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 United is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 12/311:42 pmONT - ORD
1 stop5h 48mUnited Airlines
mar. 1/78:05 pmORD - ONT
2 stops15h 46mUnited Airlines
Deal found 12/18$503

Find flights from Ontario to Illinois within your budget

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 diciembre 19, 2024.

Fly from

Any airport

Fly to

Any airport

Route

Depart

Return

Price

OntarioSt. Louis

ONT - STL

ONTSTL

Ontario

lun. 1/6

1:05 pm-8:29 pm

1 stop5h 24m

Lambert-St Louis

sáb. 1/11

6:46 pm-11:44 pm

1 stop6h 58m

$106

OntarioChicago

ONT - ORD

ONTORD

Ontario

vie. 1/10

10:40 am-12:35 am

1 stop11h 55m

Chicago O'Hare Intl

lun. 1/13

6:20 am-8:25 pm

1 stop16h 05m

$145

OntarioChicago

ONT - MDW

ONTMDW

Ontario

jue. 1/9

6:42 pm-11:48 am

1 stop15h 06m

Chicago Midway

dom. 1/12

12:43 pm-7:14 am

1 stop20h 31m

$146

OntarioChicago

ONT - ORD

ONTORD

Ontario

mié. 1/29

3:04 pm-11:59 pm

1 stop6h 55m

Chicago O'Hare Intl

mar. 2/4

11:47 am-6:37 pm

1 stop8h 50m

$168

OntarioChicago

ONT - ORD

ONTORD

Ontario

jue. 1/16

7:56 am-5:25 pm

1 stop7h 29m

Chicago O'Hare Intl

mié. 1/29

2:07 pm-8:13 pm

1 stop8h 06m

$182

OntarioChicago

ONT - ORD

ONTORD

Ontario

vie. 2/7

4:06 pm-2:03 pm

1 stop19h 57m

Chicago O'Hare Intl

lun. 2/10

3:35 pm-10:34 am

1 stop20h 59m

$210

OntarioSt. Louis

ONT - STL

ONTSTL

Ontario

jue. 1/16

7:56 am-7:31 pm

1 stop9h 35m

Lambert-St Louis

jue. 1/23

2:49 pm-10:39 pm

1 stop9h 50m

$253

OntarioChicago

ONT - MDW

ONTMDW

Ontario

jue. 1/30

7:05 am-4:21 pm

1 stop7h 16m

Chicago Midway

sáb. 2/1

3:41 pm-10:52 pm

1 stop9h 11m

$256

OntarioChicago

ONT - ORD

ONTORD

Ontario

vie. 1/17

1:21 pm-9:22 pm

1 stop6h 01m

Chicago O'Hare Intl

mié. 1/22

7:15 am-12:26 pm

1 stop7h 11m

$256

OntarioSt. Louis

ONT - STL

ONTSTL

Ontario

mar. 1/14

6:00 am-1:18 pm

1 stop5h 18m

Lambert-St Louis

mar. 1/21

5:00 pm-10:52 pm

1 stop7h 52m

$316

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/18

Showing 1-10 of 42 results
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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.
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.

Travel insights for flights from Ontario to Illinois

Get recent, data-driven insights about flights from Ontario to Illinois including ideal travel times, pricing trends, and more.

What is the cheapest month to book a flight from Ontario to Illinois?

Currently, September is the cheapest month in which you can book a flight from Ontario to Illinois (average of $232). Flying from Ontario to Illinois in June is currently the most expensive (average of $308). 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 diciembre 19, 2024.

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.

Rainfall in Illinois by month

Plan your trip to Illinois by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Illinois ranges from 1.7 - 4.9 inches per month. August is typically the wettest month, when rainfall can reach 4.9 in. January is typically the driest time to visit Illinois when rainfall is around 1.7 in.

Temperature in Illinois by month

Plan your trip to Illinois by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Illinois, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 73.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 23.0 F).

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 diciembre 19, 2024.
Get a feel of what it's like to fly with Alaska Airlines, American Airlines and Frontier from Ontario to Illinois by reading reviews from past customers. In addition to providing an overall rating, users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.1
Very good
4,836 reviews

Crew

8.7

Food

7.2

Comfort

8.1

Entertainment

7.7

Boarding

8.2

Overall

8.1

Reviews

1 / 10

My original flight was delayed so they found this flight for me so I could arrive at a reasonable time

Southwest
8.1
Very good
4,836 reviews
Southwest
8.1
Very good
4,836 reviews

Crew

8.7

Food

7.2

Comfort

8.1

Entertainment

7.7

Boarding

8.2

Overall

8.1

Reviews

1 / 10

My original flight was delayed so they found this flight for me so I could arrive at a reasonable time

Alaska Airlines
8.0
Very good
9,552 reviews
Southwest
8.1
Very good
4,836 reviews

Crew

8.7

Food

7.2

Comfort

8.1

Entertainment

7.7

Boarding

8.2

Overall

8.1

Reviews

1 / 10

My original flight was delayed so they found this flight for me so I could arrive at a reasonable time

Delta
8.0
Very good
8,600 reviews
Southwest
8.1
Very good
4,836 reviews

Crew

8.7

Food

7.2

Comfort

8.1

Entertainment

7.7

Boarding

8.2

Overall

8.1

Reviews

1 / 10

My original flight was delayed so they found this flight for me so I could arrive at a reasonable time

United Airlines
7.4
Good
9,048 reviews
Southwest
8.1
Very good
4,836 reviews

Crew

8.7

Food

7.2

Comfort

8.1

Entertainment

7.7

Boarding

8.2

Overall

8.1

Reviews

1 / 10

My original flight was delayed so they found this flight for me so I could arrive at a reasonable time

American Airlines
7.2
Good
10,000 reviews
Southwest
8.1
Very good
4,836 reviews

Crew

8.7

Food

7.2

Comfort

8.1

Entertainment

7.7

Boarding

8.2

Overall

8.1

Reviews

1 / 10

My original flight was delayed so they found this flight for me so I could arrive at a reasonable time

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.

  • What airport do you fly from for flights from Ontario to Illinois?

    Ontario (ONT), located 3.1 mi from the city center, is the airport you fly out of when you book flights from Ontario to Illinois.

  • What are the cheapest airlines to fly from Ontario to Illinois one-way?

    $54 is the cheapest one-way deal found within the past few days, from Frontier. You may also be able to find cheap deals on Alaska Airlines and American Airlines, with prices starting from $123 and $124, respectively.

  • What are the most popular routes from Ontario to Illinois?

    The most popular flight routes from Ontario to Illinois are Ontario - Chicago O'Hare Intl, Ontario - Chicago Midway and Ontario - Lambert-St Louis.

  • Can I find deals for flights from Ontario to Illinois that include hotel bookings?

    Yes. In addition to deals on Ontario to Illinois flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Ontario to Illinois?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Ontario to Illinois.

  • Can I find deals for business class flights from Ontario to Illinois?

    Yes. Cheapflights offers flight deals from Ontario to Illinois by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Ontario to Illinois?

    Currently, September is the cheapest month in which you can book a flight from Ontario to Illinois (average of $232). Flying from Ontario to Illinois in June is currently the most expensive (average of $308). 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.

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Alternative routes for Ontario to Illinois

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Top 6 airlines flying from Ontario to Illinois

Discover the top 6 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 diciembre 19, 2024.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$92Average$195FlexibilityNo cancel feeOn-time65%
FrontierCheapest$109Average$213FlexibilityNo cancel feeOn-time62%
DeltaCheapest$236Average$450FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$254Average$595FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$273Average$515FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$358Average$505FlexibilityNo cancel feeOn-time63%
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