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$52+ Cheap flights from Illinois to Ontario (ONT)

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 12/7. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — ONT
Nov 26 — Dec 31
Tue 11/26
Tue 12/3
1 adult, Economy
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Cheap flight deals from Illinois to Ontario

Discover tips and strategies to find the most affordable flight options for your journey from Illinois (USIL) to Ontario (ONT). 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 21, 2024.

Find flight deals from Illinois to Ontario

Cheapest flights from Illinois to Ontario
Explore the most affordable flight options available from Illinois to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on November 21, 2024.

This CheapOair 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/76:46 pmSTL - ONT
1 stop6h 58mFrontier
Thu 12/126:45 amONT - STL
1 stop23h 28mFrontier
Deal found 11/20$118
This Mytrip 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/57:25 amORD - ONT
1 stop18h 19mFrontier
Wed 12/1112:34 pmONT - ORD
1 stop26h 54mFrontier
Deal found 11/20$133
This FlightHub 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/97:15 amMDW - ONT
1 stop7h 45mFrontier
Wed 12/117:45 amONT - MDW
1 stop14h 28mFrontier
Deal found 11/20$138
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.
Tue 12/177:10 pmORD - ONT
1 stop7h 04mDelta
Wed 12/251:05 pmONT - ORD
1 stop6h 34mDelta
Deal found 11/20$256
This Expedia 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/76:46 pmSTL - ONT
1 stop6h 58mMultiple Airlines
Thu 12/127:00 amONT - STL
2 stops14h 59mMultiple Airlines
Deal found 11/20$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.
Tue 12/176:30 pmSTL - ONT
1 stop7h 44mDelta
Tue 1/71:21 pmONT - STL
1 stop6h 12mDelta
Deal found 11/20$306
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.
Tue 12/107:00 amORD - ONT
1 stop7h 58mAlaska Airlines
Fri 12/138:55 pmONT - ORD
1 stop24h 52mAlaska Airlines
Deal found 11/20$309
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 12/172:29 pmSTL - ONT
1 stop5h 58mAmerican Airlines
Tue 12/2410:02 amONT - STL
2 stops7h 28mAmerican Airlines
Deal found 11/19$311
This eDestinos 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 eDestinos is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/219:54 pmORD - ONT
1 stop12h 12mMultiple Airlines
Sat 1/47:00 pmONT - ORD
3 stops50h 46mMultiple Airlines
Deal found 11/20$327
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 12/117:00 amSTL - ONT
1 stop7h 58mAlaska Airlines
Sun 12/157:00 amONT - STL
2 stops14h 59mAlaska Airlines
Deal found 11/20$370
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.
Fri 12/132:15 pmMDW - ONT
2 stops11h 59mDelta
Sun 12/1510:00 pmONT - MDW
1 stop9h 50mDelta
Deal found 11/20$371
This Southwest 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/186:05 amSTL - ONT
1 stop6h 50mSouthwest
Fri 1/39:40 amONT - STL
2 stops7h 50mSouthwest
Deal found 11/20$382

Find flights from Illinois to Ontario within your budget

Customize your flight search to find flights from Illinois to Ontario 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 21, 2024.

Fly from

Any airport

Fly to

Any airport

Route

Depart

Return

Price

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Sat 12/7

6:46 pm-11:44 pm

1 stop6h 58m

Ontario

Thu 12/12

6:45 am-8:13 am

1 stop23h 28m

$118

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

Tue 1/21

8:15 am-11:47 pm

1 stop17h 32m

Ontario

Sat 1/25

7:59 pm-11:44 am

1 stop13h 45m

$132

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Thu 12/5

7:25 am-11:44 pm

1 stop18h 19m

Ontario

Wed 12/11

12:34 pm-5:28 pm

1 stop26h 54m

$133

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Sat 1/4

9:54 pm-3:26 pm

1 stop19h 32m

Ontario

Sat 1/11

7:59 pm-5:30 am

1 stop7h 31m

$187

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Wed 1/29

11:47 am-6:24 pm

2 stops8h 37m

Ontario

Fri 1/31

2:44 pm-11:50 pm

1 stop7h 06m

$223

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Thu 1/9

12:45 pm-5:57 pm

1 stop7h 12m

Ontario

Mon 1/13

10:47 am-7:59 pm

1 stop7h 12m

$246

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Thu 1/9

3:35 pm-10:13 pm

1 stop8h 38m

Ontario

Mon 1/13

11:33 am-11:59 pm

1 stop10h 26m

$252

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Sat 1/25

7:20 am-12:26 pm

1 stop7h 06m

Ontario

Tue 1/28

7:00 am-3:45 pm

1 stop6h 45m

$256

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

Thu 1/9

10:19 am-10:32 pm

2 stops14h 13m

Ontario

Wed 1/15

1:00 pm-10:20 pm

1 stop7h 20m

$261

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Sat 12/7

6:46 pm-11:44 pm

1 stop6h 58m

Ontario

Thu 12/12

7:00 am-11:59 pm

2 stops14h 59m

$282

Flights are sorted by cheapest round-trip flights first.

Deals found on 11/19

Showing 1-10 of 52 results
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Best time to book a flight from Illinois to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from Illinois 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 Illinois to Ontario

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

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

Currently, September is the cheapest month in which you can book a flight from Illinois to Ontario (average of $236). Flying from Illinois to Ontario in December is currently the most expensive (average of $298). 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 IL to ONT?

Find hourly flight availability from Illinois to Ontario. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated November 21, 2024.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Illinois to Ontario as you normally would.

Rainfall in Ontario by month

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

In terms of precipitation, rainfall in Ontario ranges from 0.1 - 3.4 inches per month. February is typically the wettest month, when rainfall can reach 3.4 in. June is typically the driest time to visit Ontario when rainfall is around 0.1 in.

Temperature in Ontario by month

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

If weather is an important factor for your trip to Ontario, use this chart to help with planning. For those seeking warmer temperatures, August is the ideal time of year to visit, when temperatures reach an average of 78.8 F. Travelers looking to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 53.6 F).

Reviews of airlines servicing Ontario

Get insights into the airlines that provide service to Ontario. 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 Ontario. Reviews last updated November 21, 2024.
Get a feel of what it's like to fly with American Airlines, Frontier and United Airlines from Illinois to Ontario 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
5,015 reviews

Food

7.2

Comfort

8.1

Boarding

8.2

Entertainment

7.7

Crew

8.7

Overall

8.1

Reviews

1 / 10

My first time, surprisingly good! It was a good ride overall. Coming from Singapore, this budget flight is better than the budget airline for our national carrier Singapore Airlines.

Southwest
8.1
Very good
5,015 reviews
Southwest
8.1
Very good
5,015 reviews

Food

7.2

Comfort

8.1

Boarding

8.2

Entertainment

7.7

Crew

8.7

Overall

8.1

Reviews

1 / 10

My first time, surprisingly good! It was a good ride overall. Coming from Singapore, this budget flight is better than the budget airline for our national carrier Singapore Airlines.

Alaska Airlines
8.0
Very good
9,458 reviews
Southwest
8.1
Very good
5,015 reviews

Food

7.2

Comfort

8.1

Boarding

8.2

Entertainment

7.7

Crew

8.7

Overall

8.1

Reviews

1 / 10

My first time, surprisingly good! It was a good ride overall. Coming from Singapore, this budget flight is better than the budget airline for our national carrier Singapore Airlines.

Delta
8.0
Very good
8,758 reviews
Southwest
8.1
Very good
5,015 reviews

Food

7.2

Comfort

8.1

Boarding

8.2

Entertainment

7.7

Crew

8.7

Overall

8.1

Reviews

1 / 10

My first time, surprisingly good! It was a good ride overall. Coming from Singapore, this budget flight is better than the budget airline for our national carrier Singapore Airlines.

United Airlines
7.4
Good
9,172 reviews
Southwest
8.1
Very good
5,015 reviews

Food

7.2

Comfort

8.1

Boarding

8.2

Entertainment

7.7

Crew

8.7

Overall

8.1

Reviews

1 / 10

My first time, surprisingly good! It was a good ride overall. Coming from Singapore, this budget flight is better than the budget airline for our national carrier Singapore Airlines.

American Airlines
7.2
Good
10,000 reviews
Southwest
8.1
Very good
5,015 reviews

Food

7.2

Comfort

8.1

Boarding

8.2

Entertainment

7.7

Crew

8.7

Overall

8.1

Reviews

1 / 10

My first time, surprisingly good! It was a good ride overall. Coming from Singapore, this budget flight is better than the budget airline for our national carrier Singapore Airlines.

Related info for your journey

Find useful and relevant information for your journey from Illinois to Ontario. 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 into for flights to Ontario from Illinois?

    Located just 3.1 mi from the city center, Ontario (ONT) is the airport most travelers will use when flying to Ontario from Illinois.

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

    $52 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 Alaska Airlines, with prices starting from $109 and $123, respectively.

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

    When deciding which route to take from Illinois to Ontario consider Chicago O'Hare Intl - Ontario, Chicago Midway - Ontario or Lambert-St Louis - Ontario as they are the most popular.

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

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

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

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

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

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

    Currently, September is the cheapest month in which you can book a flight from Illinois to Ontario (average of $236). Flying from Illinois to Ontario in December is currently the most expensive (average of $298). 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

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Alternative routes for Illinois to Ontario

See prices for flight routes from nearby airports that may be better suited for you.
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Top 6 airlines flying from Illinois to Ontario

Discover the top 6 airlines that operate flights from Illinois to Ontario. 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 21, 2024.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$121Average$200FlexibilityNo cancel feeOn-time62%
Spirit AirlinesCheapest$122Average$229FlexibilityNo cancel feeOn-time65%
American AirlinesCheapest$204Average$543FlexibilityNo cancel feeOn-time71%
DeltaCheapest$256Average$382FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$256Average$500FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$293Average$540FlexibilityNo cancel feeOn-time69%
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