HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Illinois

$53+ 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 1/6. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — ORD
Nov 25 — Dec 21
Mon 11/25
Mon 12/2
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Ontario to Illinois with Cheapflights

1. Tell us where you want to go
Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”
2. Select your favorite providers
We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.
3. Compare prices and book
Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheap flight deals from Ontario to Illinois

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 November 20, 2024.

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 November 20, 2024.

This Frontier deal was found by Cheapflights users on 11/19. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/58:04 amONT - STL
1 stop9h 30mFrontier
Sat 12/76:46 pmSTL - ONT
1 stop6h 58mFrontier
Deal found 11/19$108
This Frontier deal was found by Cheapflights users on 11/18. 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.
Thu 12/58:56 amONT - MDW
1 stop10h 06mFrontier
Mon 12/97:15 amMDW - ONT
1 stop7h 45mFrontier
Deal found 11/18$128
This Frontier deal was found by Cheapflights users on 11/20. 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.
Thu 12/58:56 amONT - ORD
1 stop11h 11mFrontier
Fri 1/248:25 pmORD - ONT
1 stop12h 46mFrontier
Deal found 11/20$128
This eDestinos deal was found by Cheapflights users on 11/18. 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 eDestinos is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/1810:39 pmONT - ORD
1 stop28h 51mMultiple Airlines
Wed 12/256:00 amORD - ONT
2 stops28h 06mMultiple Airlines
Deal found 11/18$241
This Alaska Airlines deal was found by Cheapflights users on 11/20. 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.
Wed 12/111:53 pmONT - ORD
1 stop7h 54mAlaska Airlines
Thu 1/93:35 pmORD - ONT
1 stop8h 38mAlaska Airlines
Deal found 11/20$251
This United Airlines deal was found by Cheapflights users on 11/18. 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 Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/286:50 pmONT - ORD
1 stop9h 04mUnited Airlines
Thu 1/28:45 amORD - ONT
1 stop5h 55mUnited Airlines
Deal found 11/18$282
This Delta deal was found by Cheapflights users on 11/20. 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.
Sat 12/77:10 amONT - ORD
1 stop7h 33mDelta
Tue 12/103:40 pmORD - ONT
1 stop9h 22mDelta
Deal found 11/20$284
This Delta deal was found by Cheapflights users on 11/20. 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.
Sat 12/712:05 pmONT - MDW
1 stop8h 01mDelta
Tue 12/102:15 pmMDW - ONT
2 stops10h 47mDelta
Deal found 11/20$289
This American Airlines deal was found by Cheapflights users on 11/19. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/116:10 amONT - STL
1 stop5h 22mAmerican Airlines
Sat 12/147:20 amSTL - ONT
1 stop6h 40mAmerican Airlines
Deal found 11/19$306
This American Airlines deal was found by Cheapflights users on 11/18. 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.
Fri 12/134:25 pmONT - ORD
1 stop6h 20mAmerican Airlines
Sat 1/186:00 amORD - ONT
1 stop7h 58mAmerican Airlines
Deal found 11/18$306
This American Airlines deal was found by Cheapflights users on 11/19. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/312:53 pmONT - MLI
1 stop6h 46mAmerican Airlines
Tue 12/106:00 amMLI - ONT
2 stops14h 27mAmerican Airlines
Deal found 11/19$317
This Delta deal was found by Cheapflights users on 11/18. 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.
Wed 12/1111:18 amONT - STL
2 stops11h 39mDelta
Sun 12/157:20 amSTL - ONT
1 stop7h 05mDelta
Deal found 11/18$335

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 2,629,791 searches. Data last updated November 20, 2024.

Fly from

Any airport

Fly to

Any airport

Route

Depart

Return

Price

OntarioSt. Louis

ONT - STL

ONTSTL

Ontario

Thu 12/5

8:04 am-7:34 pm

1 stop9h 30m

Lambert-St Louis

Wed 12/11

6:46 pm-11:44 pm

1 stop6h 58m

$108

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Thu 12/5

8:56 am-9:02 pm

1 stop10h 06m

Chicago Midway

Mon 12/9

7:15 am-1:00 pm

1 stop7h 45m

$128

OntarioChicago

ONT - ORD

ONTORD

Ontario

Thu 12/5

8:56 am-10:07 pm

1 stop11h 11m

Chicago O'Hare Intl

Mon 12/9

7:25 am-1:00 pm

1 stop7h 35m

$128

OntarioChicago

ONT - ORD

ONTORD

Ontario

Wed 12/18

10:39 pm-5:30 am

1 stop28h 51m

Chicago O'Hare Intl

Wed 12/25

6:00 am-8:06 am

2 stops28h 06m

$241

OntarioChicago

ONT - ORD

ONTORD

Ontario

Wed 1/22

7:00 am-5:38 pm

1 stop8h 38m

Chicago O'Hare Intl

Tue 1/28

11:47 am-6:37 pm

1 stop8h 50m

$246

OntarioChicago

ONT - ORD

ONTORD

Ontario

Wed 12/11

1:53 pm-11:47 pm

1 stop7h 54m

Chicago O'Hare Intl

Thu 1/9

3:35 pm-10:13 pm

1 stop8h 38m

$251

OntarioChicago

ONT - ORD

ONTORD

Ontario

Tue 2/4

6:00 am-2:12 pm

1 stop6h 12m

Chicago O'Hare Intl

Tue 2/18

7:20 pm-11:53 pm

1 stop6h 33m

$256

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Wed 1/22

6:00 am-5:47 pm

2 stops9h 47m

Chicago Midway

Tue 1/28

6:00 am-11:50 am

1 stop7h 50m

$261

OntarioSt. Louis

ONT - STL

ONTSTL

Ontario

Fri 1/24

11:14 am-11:59 pm

2 stops10h 45m

Lambert-St Louis

Sun 1/26

8:31 pm-7:11 am

1 stop12h 40m

$276

OntarioChicago

ONT - ORD

ONTORD

Ontario

Sat 12/28

6:50 pm-5:54 am

1 stop9h 04m

Chicago O'Hare Intl

Thu 1/2

8:45 am-12:40 pm

1 stop5h 55m

$282

Flights are sorted by cheapest round-trip flights first.

Deals found on 11/19

Showing 1-10 of 52 results
1
2
3
...
6

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 November 20, 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 November 20, 2024.
Get a feel of what it's like to fly with American Airlines, Frontier and United Airlines 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
5,014 reviews

Overall

8.1

Entertainment

7.7

Comfort

8.1

Crew

8.7

Boarding

8.2

Food

7.2

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
5,014 reviews
Southwest
8.1
Very good
5,014 reviews

Overall

8.1

Entertainment

7.7

Comfort

8.1

Crew

8.7

Boarding

8.2

Food

7.2

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
9,461 reviews
Southwest
8.1
Very good
5,014 reviews

Overall

8.1

Entertainment

7.7

Comfort

8.1

Crew

8.7

Boarding

8.2

Food

7.2

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
8,756 reviews
Southwest
8.1
Very good
5,014 reviews

Overall

8.1

Entertainment

7.7

Comfort

8.1

Crew

8.7

Boarding

8.2

Food

7.2

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
9,171 reviews
Southwest
8.1
Very good
5,014 reviews

Overall

8.1

Entertainment

7.7

Comfort

8.1

Crew

8.7

Boarding

8.2

Food

7.2

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
5,014 reviews

Overall

8.1

Entertainment

7.7

Comfort

8.1

Crew

8.7

Boarding

8.2

Food

7.2

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?

    $53 is the cheapest one-way deal found within the past few days, from Frontier. You may also be able to find cheap deals on American Airlines and United Airlines, with prices starting from $109 and $119, 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.

See more FAQs

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Ontario to Illinois

See prices for flight routes from nearby airports that may be better suited for you.
Los Angeles to John F Kennedy Intl flights
Los Angeles to Newark flights
San Francisco to John F Kennedy Intl flights
Los Angeles to Dallas/Fort Worth flights
Los Angeles to Honolulu flights
Los Angeles to Seattle flights
Los Angeles to LaGuardia flights
Los Angeles to Miami flights
Los Angeles to San Francisco flights
San Francisco to Newark flights
Los Angeles to O'Hare Intl flights
Los Angeles to Orlando flights
San Francisco to Los Angeles flights
San Francisco to Seattle flights
San Francisco to Las Vegas flights
Los Angeles to Las Vegas flights
Los Angeles to Fort Lauderdale flights
San Francisco to LaGuardia flights
Santa Ana to Las Vegas flights
Santa Ana to Newark flights
Los Angeles to Boston flights
San Francisco to Honolulu flights
Burbank to Las Vegas flights
Ontario to Dallas/Fort Worth flights
San Francisco to Dallas/Fort Worth flights
Los Angeles to San Jose flights
Los Angeles to Hobby flights
San Jose to Las Vegas flights
San Diego to John F Kennedy Intl flights
San Jose to Los Angeles flights
Los Angeles to Reagan-National flights
Los Angeles to Oakland flights
Los Angeles to Dulles Intl flights
Oakland to Los Angeles flights
Los Angeles to George Bush Intcntl flights
Los Angeles to Portland flights
San Francisco to Miami flights
Burbank to Newark flights
San Francisco to Ontario flights
Los Angeles to Atlanta flights
Oakland to Las Vegas flights
Ontario to San Francisco flights
Burbank to LaGuardia flights
Los Angeles to Baltimore flights
Ontario to Seattle flights
San Francisco to O'Hare Intl flights
Los Angeles to New Orleans flights
San Diego to Newark flights
San Francisco to Dulles Intl flights
Los Angeles to Salt Lake City flights

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 2,629,791 searches. Data last updated November 20, 2024.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$92Average$197FlexibilityNo cancel feeOn-time65%
FrontierCheapest$109Average$211FlexibilityNo cancel feeOn-time62%
DeltaCheapest$236Average$392FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$254Average$597FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$278Average$511FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$336Average$480FlexibilityNo cancel feeOn-time63%
100% Free
Cheapflights is completely free to use, so you can start saving the moment you arrive.
Book with Flexibility
Our users can plan ahead with confidence and find flights with no change fees
Travel Smart
Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.
View all available airlines