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 17m on average, while flying from Moline to Los Angeles is 6h 12m on average. Los Angeles is the most popular airport in Ontario.

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

14 flights are operational weekly from Illinois to Ontario as of July 2026. The most popular departure day for this route is Mon, with 21% of flights per week taking off on this day.

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

As of July 2026, 2 flights take off from Illinois and land in Ontario each day. The most common flight departure time for this route is 11:00AM, with 55% of daily flights taking off in the evening.

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

United Airlines, Frontier, and Delta are the most popular carriers operating 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 July 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.

$89 Cheap Flights from Illinois to Ontario in 2026

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Find the cheapest flights from Illinois to Los Angeles

Round-trip

One-way

Last minute

Direct

Cheap round-trip flights

Enter your travel dates to find the best prices.

7:58 pm - 10:04 am

STL

ONT

16h 06m

1 stop

6:00 am - 7:13 pm

ONT

STL

11h 13m

1 stop

$175Frontier

Mon, Aug 24 - Mon, Aug 31

11:06 am - 11:55 pm

ORD

ONT

14h 49m

1 stop

6:15 am - 10:01 am

ONT

ORD

25h 46m

1 stop

$177Frontier

Wed, Oct 28 - Mon, Nov 2

2:00 pm - 4:10 pm

MDW

ONT

4h 10mnonstop

11:55 pm - 5:45 am

ONT

MDW

3h 50mnonstop

$239Southwest

Mon, Aug 17 - Mon, Aug 24

5:25 pm - 7:40 pm

MDW

ONT

4h 15mnonstop

11:55 pm - 5:45 am

ONT

MDW

3h 50mnonstop

$239Southwest

Tue, Sep 15 - Mon, Sep 21

4:15 pm - 6:47 pm

ORD

ONT

4h 32mnonstop

1:00 pm - 11:19 pm

ONT

ORD

8h 19m

1 stop

$249United Airlines

Mon, Nov 23 - Wed, Dec 2

8:33 pm - 10:59 pm

ORD

ONT

4h 26mnonstop

1:56 pm - 12:59 am

ONT

ORD

9h 03m

1 stop

$249United Airlines

Sat, Sep 19 - Mon, Sep 21

7:35 am - 12:10 pm

ORD

ONT

6h 35m

1 stop

1:25 pm - 9:47 pm

ONT

ORD

6h 22m

1 stop

$259Delta

Wed, Nov 18 - Thu, Dec 3

4:45 pm - 10:23 pm

ORD

ONT

7h 38m

1 stop

1:06 pm - 9:33 pm

ONT

ORD

6h 27m

1 stop

$259Delta

Sat, Aug 29 - Sat, Sep 5

8:20 am - 1:53 pm

ORD

ONT

7h 33m

1 stop

12:59 pm - 10:30 pm

ONT

ORD

7h 31m

1 stop

$259American Airlines

Sat, Aug 29 - Sat, Sep 5

5:00 am - 9:29 am

ORD

ONT

6h 29m

1 stop

1:04 pm - 11:43 pm

ONT

ORD

8h 39m

1 stop

$259American Airlines

Wed, Sep 16 - Thu, Sep 17

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Delta flights from Illinois to Ontario

Our best Delta deals on Illinois to Ontario flight tickets

Delta

Nov 18

ORD7:35 amChicago O'Hare Intl

6h 35m

1 stop

ONT12:10 pmOntario

Dec 3

ONT1:25 pmOntario

6h 22m

1 stop

ORD9:47 pmChicago O'Hare Intl

$259

Delta

Aug 27

ORD1:50 pmChicago O'Hare Intl

10h 02m

1 stop

ONT9:52 pmOntario

Sep 5

ONT7:05 amOntario

9h 54m

1 stop

ORD6:59 pmChicago O'Hare Intl

$260

Delta

Aug 18

ORD2:00 pmChicago O'Hare Intl

10h 45m

2 stops

ONT10:45 pmOntario

Aug 22

ONT12:00 pmOntario

9h 57m

1 stop

ORD11:57 pmChicago O'Hare Intl

$264

Frontier flights from Illinois to Ontario

Our best Frontier deals on Illinois to Ontario flight tickets

Frontier

Aug 24

STL7:58 pmLambert-St Louis

16h 06m

1 stop

ONT10:04 amOntario

Aug 31

ONT6:00 amOntario

11h 13m

1 stop

STL7:13 pmLambert-St Louis

$175

Frontier

Oct 28

ORD11:06 amChicago O'Hare Intl

14h 49m

1 stop

ONT11:55 pmOntario

Nov 2

ONT6:15 amOntario

25h 46m

1 stop

ORD10:01 amChicago O'Hare Intl

$177

Frontier

Aug 31

STL7:58 pmLambert-St Louis

16h 06m

1 stop

ONT10:04 amOntario

Sep 6

ONT6:00 amOntario

11h 13m

1 stop

STL7:13 pmLambert-St Louis

$182

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Mon 8/24

7:58 pm-10:04 am

1 stop16h 06m

Ontario

Mon 8/31

6:00 am-7:13 pm

1 stop11h 13m

$175

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Wed 10/28

11:06 am-11:55 pm

1 stop14h 49m

Ontario

Mon 11/2

6:15 am-10:01 am

1 stop25h 46m

$177

Quickest round-trip

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

Mon 8/17

2:00 pm-4:10 pm

Nonstop4h 10m

Ontario

Mon 8/24

11:55 pm-5:45 am

Nonstop3h 50m

$239

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

Tue 9/15

5:25 pm-7:40 pm

Nonstop4h 15m

Ontario

Mon 9/21

11:55 pm-5:45 am

Nonstop3h 50m

$239

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Mon 11/23

4:15 pm-6:47 pm

Nonstop4h 32m

Ontario

Wed 12/2

1:00 pm-11:19 pm

1 stop8h 19m

$249

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Sat 9/19

8:33 pm-10:59 pm

Nonstop4h 26m

Ontario

Mon 9/21

1:56 pm-12:59 am

1 stop9h 03m

$249

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Wed 11/18

7:35 am-12:10 pm

1 stop6h 35m

Ontario

Thu 12/3

1:25 pm-9:47 pm

1 stop6h 22m

$259

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Sat 8/29

4:45 pm-10:23 pm

1 stop7h 38m

Ontario

Sat 9/5

1:06 pm-9:33 pm

1 stop6h 27m

$259

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Sat 8/29

8:20 am-1:53 pm

1 stop7h 33m

Ontario

Sat 9/5

12:59 pm-10:30 pm

1 stop7h 31m

$259

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Wed 9/16

5:00 am-9:29 am

1 stop6h 29m

Ontario

Thu 9/17

1:04 pm-11:43 pm

1 stop8h 39m

$259

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 $326. If you aren’t able to travel during the month of October, then book flights to Ontario from Illinois during August instead. Flights to Ontario in August, while not as cheap as those in October, still average around $350.

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 Wednesday when prices can be found for as low as $434. 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 $831.

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 $268. 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 $543 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 O'Hare Intl 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.

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	$119
Fastest flight time	4h 05m
Direct flights	Every day
Airports in Ontario	1 airport

The best one-way flight to Ontario from Illinois in the past 72 hours is $119. The best round-trip flight deal from Illinois to Ontario found on momondo in the last 72 hours is $268.

The fastest flight from Illinois to Ontario takes 4h 05m

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 July 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 22.82% of all bookings. The subsequent popular models are Boeing 737-900 at 14.56%, Boeing 737-800 at 11.65%, and Airbus A321neo at 11.17%.

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 2,753 reviews	Search Frontier flights
Delta	PriceFrom $236	Free Cancellation	Rating 7.8 8,483 reviews	Search Delta flights
Southwest	PriceFrom $268	Free Cancellation	Rating 8.0 4,228 reviews	Search Southwest flights
American Airlines	PriceFrom $300	Free Cancellation	Rating 7.1 11,839 reviews	Search American Airlines flights
United Airlines	PriceFrom $307	Free Cancellation	Rating 7.4 10,048 reviews	Search United Airlines flights

Why use momondo?

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 $88

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 8/24. 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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Delta flights from Illinois to Ontario

Our best Delta deals on Illinois to Ontario flight tickets

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Our best Frontier deals on Illinois to Ontario flight tickets

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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?

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

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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.

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