HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Chicago

$96+ Cheap flights from Ontario (ONT) to Chicago (CHI)

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 5/24. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — CHI
Apr 21 — Apr 281
Mon 4/21
Mon 4/28
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Ontario to Chicago 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.

Cheapflights Tip: The best prices from Ontario to Chicago are usually found in November or September, booked 79 days in advance, depart on a Tuesday or Wednesday and return on a Saturday

Cheap flight deals from Ontario to Chicago

Discover tips and strategies to find the most affordable flight options for your journey from Ontario (ONT) to Chicago (CHI). 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 April 16, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

Flightnetwork
3 stars

Round-trip from

$218
(Booking.com)

One-way from

$96
(Mytrip)

Popular in

March

Cheapest in

November

Average price

$311

Good round-trip deal

$317 or less

Good one-way deal

$158 or less
Provider with most accurate pricing for Ontario-Chicago (CHI) flight deals.
Search Deals
Provider most trusted by Cheapflights users for Ontario-Chicago (CHI) flights.
Search Deals
From Ontario to Chicago (CHI)
Search Deals
One-way flight from Ontario to Chicago (CHI)
Search Deals
Highest demand for flights based on searches. 9% potential increase in price ($33 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($10 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in April 2025
Search Deals
Price to beat on a round-trip flight from Ontario to Chicago (CHI).
Search Deals
Price to beat on a one-way flight from Ontario to Chicago (CHI).
Search Deals

Find flight deals from Ontario to Chicago

Cheapest flights from Ontario to Chicago
Explore the most affordable flight options available from Ontario to Chicago. Find the lowest fares from popular airlines and budget airlines, with prices last updated on April 16, 2025.

This Frontier deal was found by Cheapflights users on 4/15. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/219:31 amONT - MDW
1 stop11h 10mFrontier
Mon 4/286:15 amMDW - ONT
1 stop11h 24mFrontier
Deal found 4/15$218
This Frontier deal was found by Cheapflights users on 4/16. 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 4/247:30 pmONT - ORD
1 stop13h 06mFrontier
Mon 4/285:24 pmORD - ONT
1 stop8h 35mFrontier
Deal found 4/16$218
This United Airlines deal was found by Cheapflights users on 4/16. 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.
Thu 6/267:00 amONT - ORD
Nonstop4h 02mUnited Airlines
Mon 6/307:40 pmORD - ONT
Nonstop4h 31mUnited Airlines
Deal found 4/16$227
This Alaska Airlines deal was found by Cheapflights users on 4/16. 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 8/217:10 amONT - ORD
1 stop19h 54mAlaska Airlines
Tue 8/268:42 pmORD - ONT
1 stop16h 03mAlaska Airlines
Deal found 4/16$246
This Southwest deal was found by Cheapflights users on 4/14. 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 9/172:10 pmONT - MDW
1 stop7h 55mSouthwest
Fri 9/195:35 amMDW - ONT
1 stop5h 35mSouthwest
Deal found 4/14$247
This American Airlines deal was found by Cheapflights users on 4/14. 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 7/154:45 pmONT - ORD
1 stop5h 52mAmerican Airlines
Tue 7/297:34 amORD - ONT
1 stop6h 26mAmerican Airlines
Deal found 4/14$247
This Southwest deal was found by Cheapflights users on 4/15. 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 7/221:45 pmONT - ORD
1 stop7h 55mSouthwest
Sat 8/212:40 pmORD - ONT
1 stop11h 10mSouthwest
Deal found 4/15$252
This Delta deal was found by Cheapflights users on 4/15. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 6/216:00 amONT - ORD
1 stop5h 41mDelta
Sat 6/287:40 amORD - ONT
1 stop6h 37mDelta
Deal found 4/15$257
This Delta deal was found by Cheapflights users on 4/15. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/2412:18 pmONT - MDW
1 stop6h 55mDelta
Wed 5/281:08 pmMDW - ONT
2 stops12h 34mDelta
Deal found 4/15$262
This Expedia deal was found by Cheapflights users on 4/16. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/156:35 pmONT - ORD
1 stop8h 35mMultiple Airlines
Wed 5/216:00 amORD - ONT
1 stop14h 25mMultiple Airlines
Deal found 4/16$287
This lastminute.com deal was found by Cheapflights users on 4/16. 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 lastminute.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/811:46 amONT - ORD
1 stop8h 13mHawaiian Airlines
Wed 5/1412:00 pmORD - ONT
1 stop10h 29mHawaiian Airlines
Deal found 4/16$322

Cheapflights Fare Finder

Customize your flight search to find flights from Ontario to Chicago 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 April 16, 2025.
Use the filters below to find and compare flights from Ontario to Chicago that are best for you.

Fly from

Ontario

Fly to

Chicago

Route

Depart

Return

Price

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Mon 4/21

9:31 am-10:41 pm

1 stop11h 10m

Chicago Midway

Mon 4/28

6:15 am-3:39 pm

1 stop11h 24m

$218

OntarioChicago

ONT - ORD

ONTORD

Ontario

Thu 4/24

7:30 pm-10:36 am

1 stop13h 06m

Chicago O'Hare Intl

Sun 4/27

8:07 pm-7:20 am

1 stop13h 13m

$218

OntarioChicago

ONT - ORD

ONTORD

Ontario

Thu 6/26

7:00 am-1:02 pm

Nonstop4h 02m

Chicago O'Hare Intl

Mon 6/30

7:40 pm-10:11 pm

Nonstop4h 31m

$227

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Tue 6/17

5:25 pm-12:50 am

1 stop5h 25m

Chicago Midway

Sat 6/21

7:45 am-2:05 pm

1 stop8h 20m

$247

OntarioChicago

ONT - ORD

ONTORD

Ontario

Tue 7/15

4:45 pm-12:37 am

1 stop5h 52m

Chicago O'Hare Intl

Tue 7/29

7:34 am-12:00 pm

1 stop6h 26m

$247

OntarioChicago

ONT - ORD

ONTORD

Ontario

Sat 6/21

1:15 pm-10:09 pm

1 stop6h 54m

Chicago O'Hare Intl

Wed 6/25

7:20 pm-11:46 pm

1 stop6h 26m

$257

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Sat 5/24

12:18 pm-9:13 pm

1 stop6h 55m

Chicago Midway

Wed 5/28

1:08 pm-11:42 pm

2 stops12h 34m

$262

OntarioChicago

ONT - ORD

ONTORD

Ontario

Thu 5/15

6:35 pm-5:10 am

1 stop8h 35m

Chicago O'Hare Intl

Wed 5/21

6:00 am-6:25 pm

1 stop14h 25m

$287

OntarioChicago

ONT - ORD

ONTORD

Ontario

Sat 5/10

6:00 am-5:00 pm

1 stop9h 00m

Chicago O'Hare Intl

Wed 5/14

9:00 am-3:32 pm

1 stop8h 32m

$314

OntarioChicago

ONT - ORD

ONTORD

Ontario

Thu 5/8

11:46 am-9:59 pm

1 stop8h 13m

Chicago O'Hare Intl

Wed 5/14

12:00 pm-8:29 pm

1 stop10h 29m

$322

Flights are sorted by cheapest round-trip flights first.

Deals found on 4/15

Showing 1-10 of 23 results
1
2
3

Compare providers for flights from Ontario to Chicago

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Ontario to Chicago in April.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*2 stars
eDreamsPrice Accuracy3 starsTrust Score*3 stars
FlightnetworkPrice Accuracy2 starsTrust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on Ontario-Chicago flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Ontario-Chicago flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Ontario-Chicago flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Ontario-Chicago flights, Cheapflights users trust Flightnetwork the most. Flightnetwork has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Ontario-Chicago flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from Ontario to Chicago

Have a flexible travel schedule? Discover the best time to fly to Chicago 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.

Cheapflights Insights

Everything you need to know about your flight from Ontario to Chicago

How far ahead should I book a flight from Ontario to Chicago?

Use this chart to determine the optimal time to book a round-trip flight from Ontario to Chicago. Price data was last updated on April 11, 2025.

The best time to book flights from Ontario to Chicago is 79 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.

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

Currently, August is the cheapest month in which you can book a flight from Ontario to Chicago (average of $245). Flying from Ontario to Chicago in March is currently the most expensive (average of $321). 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 CHI?

Find hourly flight availability from Ontario to Chicago. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated April 16, 2025.

Unlike at noon, when flights are generally more expensive, you can save up to 54% on flights from Ontario to Chicago by exploring options for tickets in the evening.

What is the cheapest day to fly from Ontario to Chicago?

Use this chart to determine the cheapest time to fly round-trip from Ontario to Chicago. Price data was last updated on March 30, 2025.

Travelers seeking maximum savings on their Ontario to Chicago flight should consider departing on Saturday evenings when fares are most often at their lowest. Sunday at noon flights should be avoided if possible as fares are typically the most expensive at this time.

Rainfall in Chicago by month

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

In terms of precipitation, rainfall in Chicago 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 Chicago when rainfall is around 1.7 in.

Temperature in Chicago by month

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

If weather is an important factor for your trip to Chicago, 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 Chicago

Get insights into the airlines that provide service to Chicago. 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 Chicago. Reviews last updated April 16, 2025.
To help decide which airline to fly from Ontario to Chicago, see what other customers have to say about Alaska Airlines, Southwest and Delta. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
9,876 reviews

Entertainment

7.1

Boarding

8.2

Food

7.1

Overall

8.0

Crew

8.5

Comfort

7.9

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Alaska Airlines
8.0
Very good
9,876 reviews
Alaska Airlines
8.0
Very good
9,876 reviews

Entertainment

7.1

Boarding

8.2

Food

7.1

Overall

8.0

Crew

8.5

Comfort

7.9

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Southwest
8.0
Very good
4,282 reviews
Alaska Airlines
8.0
Very good
9,876 reviews

Entertainment

7.1

Boarding

8.2

Food

7.1

Overall

8.0

Crew

8.5

Comfort

7.9

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Delta
8.0
Very good
7,916 reviews
Alaska Airlines
8.0
Very good
9,876 reviews

Entertainment

7.1

Boarding

8.2

Food

7.1

Overall

8.0

Crew

8.5

Comfort

7.9

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Hawaiian Airlines
7.9
Good
2,380 reviews
Alaska Airlines
8.0
Very good
9,876 reviews

Entertainment

7.1

Boarding

8.2

Food

7.1

Overall

8.0

Crew

8.5

Comfort

7.9

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
United Airlines
7.4
Good
8,665 reviews
Alaska Airlines
8.0
Very good
9,876 reviews

Entertainment

7.1

Boarding

8.2

Food

7.1

Overall

8.0

Crew

8.5

Comfort

7.9

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

Related info for your journey

Find useful and relevant information for your journey from Ontario to Chicago. 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 Chicago?

    Ontario (ONT) is the airport you will fly out of if you book a flight from Ontario to Chicago. You should not have trouble finding flights to Chicago from Ontario; the airport handles an average of 1 outbound flight to Chicago per day. You should also have plenty of airline options to choose from since 7 airlines have flights from the Ontario airport to Chicago. It is only a 3.1 mi journey to Ontario (ONT) from Ontario’s city center.

  • What are the cheapest airlines flying from Ontario to Chicago round-trip?

    Cheapflights users have booked flights from Ontario to Chicago round-trip from $218. Other airlines that can offer you cheap pricing are United Airlines, from $227, and Southwest, from $247. These flights start at 30% lower than the current average price 3 months from now.

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

    The cheapest airlines for a one-way flight from Ontario to Chicago are Frontier ($96), United Airlines ($114), and Alaska Airlines ($123).

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

    Most travelers choose Ontario - Chicago O'Hare Intl, Ontario - Chicago Midway or Ontario - Chicago Greater Rockford when deciding on the best route from Ontario to Chicago.

  • What are the cheapest flights from Ontario to Chicago?

    On average you can expect to pay $643 for a flight from Ontario to Chicago. The cheapest flight overall is $113 while the most popular route, (Ontario - Chicago O'Hare Intl) is currently priced at $208.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Ontario to Chicago 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 Chicago?

    Currently, August is the cheapest month in which you can book a flight from Ontario to Chicago (average of $245). Flying from Ontario to Chicago in March is currently the most expensive (average of $321). 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

Traveling to a place near Ontario?

Book flights to Ontario if you plan to visit one of these locations
Merrillville
Hammond
Benton Harbor
Porter
Lansing
Valparaiso
Chesterton

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 Chicago

See prices for flight routes from nearby airports that may be better suited for you.
San Francisco to O'Hare Intl flights
Los Angeles to O'Hare Intl flights
Los Angeles to Midway flights
Ontario to O'Hare Intl flights
Santa Ana to O'Hare Intl flights
San Francisco to Midway flights
San Diego to O'Hare Intl flights
Burbank to O'Hare Intl flights
Oakland to O'Hare Intl flights
San Jose to O'Hare Intl flights
San Diego to Midway flights
Sacramento to O'Hare Intl flights
Las Vegas to O'Hare Intl flights
Ontario to Midway flights
San Francisco to St. Louis flights
Los Angeles to St. Louis flights
Santa Ana to Midway flights
Reno to O'Hare Intl flights
Long Beach to O'Hare Intl flights
Fresno to O'Hare Intl flights
Oakland to Midway flights
Palm Springs to O'Hare Intl flights
Las Vegas to Midway flights
Ontario to St. Louis flights
Sacramento to Midway flights
San Jose to Midway flights
Burbank to Midway flights
San Diego to St. Louis flights
Long Beach to Midway flights
Fresno to Midway flights
Sacramento to St. Louis flights
Las Vegas to St. Louis flights
Santa Ana to St. Louis flights
Reno to Midway flights
Palm Springs to Midway flights
Burbank to St. Louis flights
Los Angeles to Rockford flights
Los Angeles to Moline flights
Santa Barbara to O'Hare Intl flights
Los Angeles to Evansville flights
Santa Ana to Moline flights
Long Beach to St. Louis flights
San Jose to St. Louis flights
Oakland to St. Louis flights
Monterey to O'Hare Intl flights
Medford to O'Hare Intl flights
Bakersfield to O'Hare Intl flights
San Diego to Moline flights
San Luis Obispo to O'Hare Intl flights
Los Angeles to Peoria flights

Top 7 airlines flying from Ontario to Chicago

Discover the top 7 airlines that operate flights from Ontario to Chicago. 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 April 16, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$74Average$177FlexibilityNo cancel feeOn-time65%
FrontierCheapest$108Average$183FlexibilityNo cancel feeOn-time62%
Alaska AirlinesCheapest$161Average$438FlexibilityNo cancel feeOn-time75%
United AirlinesCheapest$227Average$357FlexibilityNo cancel feeOn-time69%
DeltaCheapest$241Average$409FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$246Average$372FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$246Average$455FlexibilityNo 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.
Site
©2025 Cheapflights