What is the cheapest airline that flies from Illinois to Ontario?

Southwest, Delta, and Frontier are the most popular carriers operating from Illinois to Ontario

How many flights depart from Illinois to Ontario on average per day?

As of September 2026, 1 flights take off from Illinois and land in Ontario each day. The most common flight departure time for this route is 8:00PM, with 62% of daily flights taking off in the evening.

What airlines fly to Ontario?

American Airlines, United Airlines and Frontier are the top three most popular airlines that fly to Ontario from Illinois according to our data. American Airlines is the first choice among our users, with 44% of people opting to fly with this airline when traveling to Ontario. Keep in mind that there are 7 different airlines that fly to Ontario on a routine basis, so you have a few additional options to choose from.

How long does it take to fly to Ontario?

Average flight duration from Illinois to Ontario depends on which airport you fly into and out of. Flying from Chicago to Los Angeles is 4h 18m on average, while flying from Peoria to Los Angeles is 6h 29m on average. Los Angeles is the most popular airport in Ontario.

How many flights depart from Illinois to Ontario on average per week?

11 flights are operational weekly from Illinois to Ontario as of September 2026. The most popular departure day for this route is Mon, with 27% of flights per week taking off on this day.

When did momondo last update prices for flights from Illinois to Ontario Airport?

Prices for flights from Illinois to Ontario Airport refresh daily.

How many operators does momondo search for flights from Illinois to Ontario Airport?

As of September 2026, there are 5 operators available to choose from for flights from Illinois to Ontario Airport.

How old do you have to be to fly from Illinois to Ontario Airport?

The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Illinois to Ontario Airport.

What documentation or ID do you need to fly to Ontario Airport?

The travel and health documents required for your trip to Ontario Airport can vary based on your itinerary and personal situation. As a rule, consider having multiple documents such as a national ID card or driver’s license, and a passport valid for six-months after you plan to arrive at Ontario Airport. We always recommend checking with your airline or a trusted third party such as IATA to get advice.

$81 Cheap Flights from Illinois to Ontario in 2026

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Find the cheapest flights from Illinois to Los Angeles

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Cheap round-trip flights

Enter your travel dates to find the best prices.

7:59 pm - 10:42 amSTL Lambert-St Louis-ONT Ontario

16h 43m1 stop Denver Intl

6:25 am - 3:23 pmONT Ontario-STL Lambert-St Louis

6h 58m1 stop Denver Intl

$146Frontier

Fri, Nov 13 - Wed, Nov 18

6:30 am - 11:51 pmORD Chicago O'Hare Intl-ONT Ontario

19h 21m1 stop Denver Intl

11:52 am - 12:21 amONT Ontario-ORD Chicago O'Hare Intl

10h 29m1 stop Denver Intl

$160Frontier

Wed, Nov 11 - Sat, Nov 14

6:30 am - 10:42 amORD Chicago O'Hare Intl-ONT Ontario

6h 12m1 stop Denver Intl

6:00 am - 5:37 pmONT Ontario-ORD Chicago O'Hare Intl

9h 37m1 stop Seattle/Tacoma Intl

$227Multiple Airlines

Sat, Nov 14 - Tue, Nov 17

6:30 am - 10:29 amORD Chicago O'Hare Intl-ONT Ontario

5h 59m1 stop Denver Intl

6:02 am - 6:20 pmONT Ontario-ORD Chicago O'Hare Intl

10h 18m1 stop Seattle/Tacoma Intl

$228Multiple Airlines

Tue, Oct 20 - Sat, Oct 24

3:55 pm - 6:15 pmMDW Chicago Midway-ONT Ontario

4h 20mnonstop

10:55 am - 4:40 pmONT Ontario-MDW Chicago Midway

3h 45mnonstop

$239Southwest

Wed, Dec 2 - Wed, Dec 9

7:00 pm - 9:25 pmMDW Chicago Midway-ONT Ontario

4h 25mnonstop

6:30 am - 12:20 pmONT Ontario-MDW Chicago Midway

3h 50mnonstop

$239Southwest

Sat, Oct 24 - Sat, Oct 31

8:20 pm - 10:51 pmORD Chicago O'Hare Intl-ONT Ontario

4h 31mnonstop

6:59 am - 1:02 pmONT Ontario-ORD Chicago O'Hare Intl

4h 03mnonstop

$239United Airlines

Sat, Oct 24 - Sat, Oct 31

4:15 pm - 6:47 pmORD Chicago O'Hare Intl-ONT Ontario

4h 32mnonstop

7:00 am - 12:58 pmONT Ontario-ORD Chicago O'Hare Intl

3h 58mnonstop

$239United Airlines

Sat, Nov 14 - Tue, Nov 17

8:46 pm - 11:19 pmORD Chicago O'Hare Intl-ONT Ontario

4h 33mnonstop

6:00 am - 12:15 pmONT Ontario-ORD Chicago O'Hare Intl

4h 15mnonstop

$258American Airlines

Wed, Jan 20 - Sun, Jan 24

8:46 pm - 11:19 pmORD Chicago O'Hare Intl-ONT Ontario

4h 33mnonstop

12:44 pm - 10:30 pmONT Ontario-ORD Chicago O'Hare Intl

7h 46m1 stop Dallas/Fort Worth

$268American Airlines

Wed, Jan 20 - Sun, Jan 24

Cheap last minute flights

Enter your travel dates to find the best prices.

6:30 am - 10:30 amORD Chicago O'Hare Intl-ONT Ontario

6h 00m1 stop Denver Intl

11:52 am - 12:24 amONT Ontario-ORD Chicago O'Hare Intl

10h 32m1 stop Denver Intl

$219Frontier

Sat, Sep 12 - Wed, Oct 14

6:30 am - 10:30 amORD Chicago O'Hare Intl-ONT Ontario

6h 00m1 stop Denver Intl

11:45 am - 12:23 amONT Ontario-ORD Chicago O'Hare Intl

10h 38m1 stop Denver Intl

$228Frontier

Sat, Sep 12 - Thu, Oct 1

5:05 pm - 8:55 pmMDW Chicago Midway-ONT Ontario

5h 50m1 stop Denver Intl

11:55 pm - 5:45 amONT Ontario-MDW Chicago Midway

3h 50mnonstop

$287Southwest

Sat, Sep 12 - Sat, Sep 19

4:05 pm - 8:05 pmMDW Chicago Midway-ONT Ontario

6h 00m1 stop Las Vegas Harry Reid Intl

1:00 pm - 8:50 pmONT Ontario-MDW Chicago Midway

5h 50m1 stop Denver Intl

$297Southwest

Sat, Sep 12 - Sat, Sep 19

5:00 am - 11:47 amORD Chicago O'Hare Intl-ONT Ontario

8h 47m1 stop Dallas/Fort Worth

2:22 pm - 12:14 amONT Ontario-ORD Chicago O'Hare Intl

7h 52m1 stop Dallas/Fort Worth

$297American Airlines

Sat, Sep 12 - Thu, Sep 17

6:59 am - 12:06 pmORD Chicago O'Hare Intl-ONT Ontario

7h 07m1 stop Phoenix Sky Harbor Intl

2:22 pm - 12:14 amONT Ontario-ORD Chicago O'Hare Intl

7h 52m1 stop Dallas/Fort Worth

$297American Airlines

Wed, Sep 16 - Thu, Sep 17

8:25 am - 5:19 pmORD Chicago O'Hare Intl-ONT Ontario

10h 54m2 stops Minneapolis St Paul Seattle/Tacoma Intl

6:00 am - 6:01 pmONT Ontario-ORD Chicago O'Hare Intl

10h 01m1 stop Seattle/Tacoma Intl

$302Delta

Tue, Sep 15 - Tue, Sep 22

1:55 pm - 10:40 pmORD Chicago O'Hare Intl-ONT Ontario

10h 45m2 stops Detroit Metropolitan Wayne County Seattle/Tacoma Intl

11:54 am - 11:57 pmONT Ontario-ORD Chicago O'Hare Intl

10h 03m1 stop Seattle/Tacoma Intl

$302Delta

Wed, Sep 16 - Tue, Sep 22

6:30 am - 10:30 amORD Chicago O'Hare Intl-ONT Ontario

6h 00m1 stop Denver Intl

7:59 pm - 6:20 amONT Ontario-ORD Chicago O'Hare Intl

8h 21m1 stop Seattle/Tacoma Intl

$337Multiple Airlines

Sun, Sep 13 - Thu, Sep 17

7:00 pm - 11:16 amORD Chicago O'Hare Intl-ONT Ontario

18h 16m1 stop Seattle/Tacoma Intl

2:30 pm - 5:38 amONT Ontario-ORD Chicago O'Hare Intl

13h 08m1 stop Las Vegas Harry Reid Intl

$346Multiple Airlines

Tue, Sep 15 - Wed, Sep 16

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United Airlines flights from Illinois to Ontario

Our best United Airlines deals on Illinois to Ontario flight tickets

United Airlines

Oct 31

ORD4:15 pmChicago O'Hare Intl

4h 32m

ONT6:47 pmOntario

Nov 10

ONT9:25 amOntario

8h 57m

1 stop

ORD8:22 pmChicago O'Hare Intl

$249

United Airlines

Nov 7

PIA6:25 amGreater Peoria

13h 36m

2 stops

ONT6:01 pmOntario

Nov 14

ONT1:29 pmOntario

5h 37m

1 stop

PIA9:06 pmGreater Peoria

$364

United Airlines

Nov 7

PIA6:25 amGreater Peoria

8h 08m

2 stops

ONT12:33 pmOntario

Nov 14

ONT9:25 amOntario

9h 48m

2 stops

PIA9:13 pmGreater Peoria

$369

Frontier flights from Illinois to Ontario

Our best Frontier deals on Illinois to Ontario flight tickets

Frontier

Nov 13

STL7:59 pmLambert-St Louis

16h 43m

1 stop

ONT10:42 amOntario

Nov 18

ONT6:25 amOntario

6h 58m

1 stop

STL3:23 pmLambert-St Louis

$146

Frontier

Nov 11

ORD6:30 amChicago O'Hare Intl

19h 21m

1 stop

ONT11:51 pmOntario

Nov 14

ONT11:52 amOntario

10h 29m

1 stop

ORD12:21 amChicago O'Hare Intl

$160

Frontier

Oct 5

STL8:10 pmLambert-St Louis

16h 20m

1 stop

ONT10:30 amOntario

Oct 7

ONT11:45 amOntario

10h 14m

1 stop

STL11:59 pmLambert-St Louis

$165

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

St. LouisOntario

STL Lambert-St Louis - ONT Ontario

STLONT

Lambert-St Louis

Fri 11/13

7:59 pm-10:42 am

1 stop16h 43m

Ontario

Wed 11/18

6:25 am-3:23 pm

1 stop6h 58m

$146

ChicagoOntario

ORD Chicago O'Hare Intl - ONT Ontario

ORDONT

Chicago O'Hare Intl

Wed 11/11

6:30 am-11:51 pm

1 stop19h 21m

Ontario

Sat 11/14

11:52 am-12:21 am

1 stop10h 29m

$160

ChicagoOntario

ORD Chicago O'Hare Intl - ONT Ontario

ORDONT

Chicago O'Hare Intl

Sat 11/14

6:30 am-10:42 am

1 stop6h 12m

Ontario

Tue 11/17

6:00 am-5:37 pm

1 stop9h 37m

$227

ChicagoOntario

ORD Chicago O'Hare Intl - ONT Ontario

ORDONT

Chicago O'Hare Intl

Tue 10/20

6:30 am-10:29 am

1 stop5h 59m

Ontario

Sat 10/24

6:02 am-6:20 pm

1 stop10h 18m

$228

Quickest round-trip

ChicagoOntario

MDW Chicago Midway - ONT Ontario

MDWONT

Chicago Midway

Wed 12/2

3:55 pm-6:15 pm

Nonstop4h 20m

Ontario

Wed 12/9

10:55 am-4:40 pm

Nonstop3h 45m

$239

ChicagoOntario

MDW Chicago Midway - ONT Ontario

MDWONT

Chicago Midway

Sat 10/24

7:00 pm-9:25 pm

Nonstop4h 25m

Ontario

Sat 10/31

6:30 am-12:20 pm

Nonstop3h 50m

$239

ChicagoOntario

ORD Chicago O'Hare Intl - ONT Ontario

ORDONT

Chicago O'Hare Intl

Sat 10/24

8:20 pm-10:51 pm

Nonstop4h 31m

Ontario

Sat 10/31

6:59 am-1:02 pm

Nonstop4h 03m

$239

ChicagoOntario

ORD Chicago O'Hare Intl - ONT Ontario

ORDONT

Chicago O'Hare Intl

Sat 11/14

4:15 pm-6:47 pm

Nonstop4h 32m

Ontario

Tue 11/17

7:00 am-12:58 pm

Nonstop3h 58m

$239

ChicagoOntario

ORD Chicago O'Hare Intl - ONT Ontario

ORDONT

Chicago O'Hare Intl

Wed 1/20

8:46 pm-11:19 pm

Nonstop4h 33m

Ontario

Sun 1/24

6:00 am-12:15 pm

Nonstop4h 15m

$258

ChicagoOntario

ORD Chicago O'Hare Intl - ONT Ontario

ORDONT

Chicago O'Hare Intl

Wed 1/20

8:46 pm-11:19 pm

Nonstop4h 33m

Ontario

Sun 1/24

12:44 pm-10:30 pm

1 stop7h 46m

$268

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first

How to get the cheapest flight ticket from Illinois to Ontario

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

Prices

Airlines

Other information

What is the cheapest month to fly to Ontario?

In general, October is the cheapest month to fly from Illinois to Ontario. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $346. If you aren’t able to travel during the month of October, then book flights to Ontario from Illinois during September instead. Flights to Ontario in September, while not as cheap as those in October, still average around $384.

What is the cheapest day to depart on your flight to Ontario?

The cheapest day to depart on your flight to Ontario is on a Thursday when prices can be found for as low as $425. This is often the case because there is less demand to fly during this day of the week. When flying out on a Monday, the most expensive travel day of the week, you can expect to see flight prices from Illinois to Ontario for around $740.

What is the cheapest time of day to depart on your flight to Ontario?

At noon is the cheapest time of day to fly from Illinois to Ontario when you can find flight prices for as low as $301. Flying to Ontario at noon is an ideal time because this is during off-peak travel hours. If you have a flexible travel schedule, then try to avoid flying in the morning when prices are $511 on average. Flights to Ontario from Illinois in the morning are generally more expensive because this time of day is more convenient for travelers’ schedules.

What is the cheapest Illinois to Ontario flight route?

Fly from Chicago Midway to Ontario for the best Illinois - Ontario flight prices

What cabin class options are available on Illinois to Ontario flights?

There are 4 cabin classes available to choose from on Illinois to Ontario flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Can stopping save me money on Illinois to Ontario flights?

No. A direct flight is the cheapest option for a flight between Illinois to Ontario.

Cheap Illinois to Ontario flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Illinois to Ontario

Best Price Found	$81
Fastest flight time	4h 10m
Direct flights	Every day
Airports in Ontario	1 airport

The best one-way flight to Ontario from Illinois in the past 72 hours is $81. The best round-trip flight deal from Illinois to Ontario found on momondo in the last 72 hours is $146.

The fastest flight from Illinois to Ontario takes 4h 10m

Direct flights go from Illinois to Ontario every day.

There is 1 airport in Ontario. From Illinois there are direct flights to Ontario (ONT).

Search flight deals

Frequently asked questions about flying from Illinois to Ontario

When did momondo last update prices for flights from Illinois to Ontario Airport?
Prices for flights from Illinois to Ontario Airport refresh daily.
How many operators does momondo search for flights from Illinois to Ontario Airport?
As of September 2026, there are 5 operators available to choose from for flights from Illinois to Ontario Airport.
How old do you have to be to fly from Illinois to Ontario Airport?
The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Illinois to Ontario Airport.
What documentation or ID do you need to fly to Ontario Airport?
The travel and health documents required for your trip to Ontario Airport can vary based on your itinerary and personal situation. As a rule, consider having multiple documents such as a national ID card or driver’s license, and a passport valid for six-months after you plan to arrive at Ontario Airport. We always recommend checking with your airline or a trusted third party such as IATA to get advice.
What is the most popular plane model from Illinois to Ontario?
momondo data reveals that the most frequently booked plane model on the route from Illinois to Ontario is Boeing 737 MAX 8, representing 26.32% of all bookings. The subsequent popular models are Boeing 737-800 at 22.04%, Airbus A321neo at 9.54%, and Boeing 737-900 at 7.89%.

Best airlines flying from Illinois to Ontario

Compare and see reviews for airlines that fly from Illinois to Ontario with momondo

Airline	Rating	Free Cancellation	Price
Frontier	PriceFrom $167	Free Cancellation	Rating 5.6 2,606 reviews	Search Frontier flights
Delta	PriceFrom $236	Free Cancellation	Rating 7.8 8,567 reviews	Search Delta flights
Southwest	PriceFrom $268	Free Cancellation	Rating 8.0 4,191 reviews	Search Southwest flights
United Airlines	PriceFrom $276	Free Cancellation	Rating 7.4 10,207 reviews	Search United Airlines flights
American Airlines	PriceFrom $288	Free Cancellation	Rating 7.1 12,051 reviews	Search American Airlines flights

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Why should I use momondo to find a flight deal from Illinois to Ontario?

momondo collates all your flight options in one place and lets you filter them to find the perfect flight from Illinois to Ontario. momondo saves you time and could save you money on your trip.

Can I find flights from Illinois to Ontario with flexible booking policies on momondo?

All flight searches from Illinois to Ontario on momondo can be filtered to show those which offer flexible booking policies.

How can momondo help me find flights from Illinois to Ontario?

Once all potential Illinois to Ontario flight options are in front of you, momondo lets you sort and filter flights based on preferences such as airline, price and flight times amongst many other options.

I’m not ready to book a flight from Illinois to Ontario right now. Can momondo alert me if prices change?

Price alerts on flights to Ontario from Illinois are quick and easy to set up on momondo. Simply perform a search and select the price alert feature. It is as simple as that.

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Cheap flights from Illinois to Los Angeles from $81

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Illinois to Los Angeles departing on 10/10. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.

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United Airlines flights from Illinois to Ontario

Our best United Airlines deals on Illinois to Ontario flight tickets

Frontier flights from Illinois to Ontario

Our best Frontier deals on Illinois to Ontario flight tickets

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Use the filters below to find and compare flights from Illinois to Ontario that are best for you.

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How to get the cheapest flight ticket from Illinois to Ontario

What is the cheapest month to fly to Ontario?

What is the cheapest day to depart on your flight to Ontario?

What is the cheapest time of day to depart on your flight to Ontario?

What is the cheapest Illinois to Ontario flight route?

What cabin class options are available on Illinois to Ontario flights?

Can stopping save me money on Illinois to Ontario flights?

What is the cheapest airline that flies from Illinois to Ontario?

What airlines fly to Ontario?

How many flights depart from Illinois to Ontario on average per day?

How many flights depart from Illinois to Ontario on average per week?

How long does it take to fly to Ontario?

Cheap Illinois to Ontario flight deals and tips

Best Price Found

Fastest flight time

Direct flights

Airports in Ontario

Frequently asked questions about flying from Illinois to Ontario

Best airlines flying from Illinois to Ontario

Compare and see reviews for airlines that fly from Illinois to Ontario with momondo

Why use momondo?

An easier way to manage your Ontario trip

We make it super easy to schedule, organize and travel with friends or family. Trips is free — and available to use no matter where you book.

Get notified when prices go down

Daily price changes in your inbox - only with Price Alerts.

Find better results for your trip to the United States

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Fly your favorite airline to Los Angeles

Airlines are sorted and displayed according to clicks in the past 7 days on momondo

Cabin classes currently available on flights to Los Angeles

List of cabin classes available on flights landing in Los Angeles. Availability may vary depending on flight origin and airline.

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