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 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 19m on average, while flying from Moline to Los Angeles is 6h 30m on average. Los Angeles is the most popular airport in Ontario.

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 42% of people opting to fly with this airline when traveling to Ontario. Keep in mind that there are 8 different airlines that fly to Ontario on a routine basis, so you have a few additional options to choose from.

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

6 flights are operational weekly from Illinois to Ontario as of April 2026. The most popular departure day for this route is Wed, with 33% 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 April 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.

$60 Cheap Flights from Illinois to Ontario in 2026

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Round-trip

One-way

Last minute

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Cheap round-trip flights

Enter your travel dates to find the best prices.

9:18 pm - 3:44 pm

STL

ONT

20h 26m

1 stop

10:50 am - 7:23 pm

ONT

STL

6h 33m

1 stop

$167Frontier

Mon, May 18 - Sun, May 24

9:37 pm - 10:05 am

ORD

ONT

14h 28m

1 stop

10:50 am - 8:32 pm

ONT

ORD

7h 42m

1 stop

$180Frontier

Tue, May 12 - Tue, May 19

6:51 pm - 3:44 pm

STL

ONT

22h 53m

1 stop

1:39 pm - 6:06 pm

ONT

STL

26h 27m

1 stop

$180Frontier

Tue, May 19 - Tue, May 26

4:06 pm - 7:35 am

ORD

ONT

17h 29m

1 stop

8:06 pm - 11:01 pm

ONT

ORD

24h 55m

1 stop

$209Multiple Airlines

Tue, May 19 - Tue, May 26

6:10 am - 9:50 am

MDW

ONT

5h 40m

1 stop

11:55 pm - 5:40 am

ONT

MDW

3h 45mnonstop

$229Southwest

Wed, May 27 - Tue, Jun 2

6:10 am - 11:35 am

MDW

ONT

7h 25m

1 stop

2:10 pm - 10:00 pm

ONT

MDW

5h 50m

1 stop

$239Southwest

Wed, May 27 - Tue, Jun 2

9:23 am - 4:17 pm

MDW

ONT

8h 54m

2 stops

12:07 pm - 9:09 pm

ONT

MDW

7h 02m

1 stop

$242Delta

Wed, May 27 - Tue, Jun 2

9:23 am - 4:17 pm

MDW

ONT

8h 54m

2 stops

6:00 am - 5:56 pm

ONT

MDW

9h 56m

2 stops

$247Delta

Wed, May 27 - Tue, Jun 2

12:52 pm - 8:27 pm

MLI

ONT

9h 35m

1 stop

11:59 pm - 10:39 am

ONT

MLI

8h 40m

1 stop

$369American Airlines

Tue, May 19 - Sat, May 23

7:00 am - 4:22 pm

PIA

ONT

11h 22m

2 stops

9:24 am - 11:37 pm

ONT

PIA

12h 13m

2 stops

$429American Airlines

Tue, May 12 - Sat, May 16

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Frontier flights from Illinois to Ontario

Our best Frontier deals on Illinois to Ontario flight tickets

Frontier

May 18

STL9:18 pmLambert-St Louis

20h 26m

1 stop

ONT3:44 pmOntario

May 24

ONT10:50 amOntario

6h 33m

1 stop

STL7:23 pmLambert-St Louis

$167

Frontier

May 12

ORD9:37 pmChicago O'Hare Intl

14h 28m

1 stop

ONT10:05 amOntario

May 19

ONT10:50 amOntario

7h 42m

1 stop

ORD8:32 pmChicago O'Hare Intl

$180

Frontier

May 23

ORD9:37 pmChicago O'Hare Intl

14h 28m

1 stop

ONT10:05 amOntario

May 26

ONT8:06 pmOntario

24h 55m

1 stop

ORD11:01 pmChicago O'Hare Intl

$185

United Airlines flights from Illinois to Ontario

Our best United Airlines deals on Illinois to Ontario flight tickets

United Airlines

May 27

ORD8:18 pmChicago O'Hare Intl

4h 33m

ONT10:51 pmOntario

Jun 2

ONT1:50 pmOntario

9h 09m

1 stop

ORD12:59 amChicago O'Hare Intl

$229

United Airlines

Aug 6

MLI3:52 pmMoline Quad-City

8h 59m

1 stop

ONT10:51 pmOntario

Aug 13

ONT7:00 amOntario

7h 56m

1 stop

MLI4:56 pmMoline Quad-City

$394

United Airlines

May 12

PIA5:30 pmGreater Peoria

7h 05m

1 stop

ONT10:35 pmOntario

May 16

ONT1:40 pmOntario

5h 39m

1 stop

PIA9:19 pmGreater Peoria

$419

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Mon 5/18

9:18 pm-3:44 pm

1 stop20h 26m

Ontario

Sun 5/24

10:50 am-7:23 pm

1 stop6h 33m

$167

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Tue 5/12

9:37 pm-10:05 am

1 stop14h 28m

Ontario

Tue 5/19

10:50 am-8:32 pm

1 stop7h 42m

$180

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Tue 5/19

6:51 pm-3:44 pm

1 stop22h 53m

Ontario

Tue 5/26

1:39 pm-6:06 pm

1 stop26h 27m

$180

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Tue 5/19

4:06 pm-7:35 am

1 stop17h 29m

Ontario

Tue 5/26

8:06 pm-11:01 pm

1 stop24h 55m

$209

Quickest round-trip

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

Wed 5/27

6:10 am-9:50 am

1 stop5h 40m

Ontario

Tue 6/2

11:55 pm-5:40 am

Nonstop3h 45m

$229

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

Wed 5/27

6:10 am-11:35 am

1 stop7h 25m

Ontario

Tue 6/2

2:10 pm-10:00 pm

1 stop5h 50m

$239

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

Wed 5/27

9:23 am-4:17 pm

2 stops8h 54m

Ontario

Tue 6/2

12:07 pm-9:09 pm

1 stop7h 02m

$242

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

Wed 5/27

9:23 am-4:17 pm

2 stops8h 54m

Ontario

Tue 6/2

6:00 am-5:56 pm

2 stops9h 56m

$247

MolineOntario

MLI - ONT

MLIONT

Moline Quad-City

Tue 5/19

12:52 pm-8:27 pm

1 stop9h 35m

Ontario

Sat 5/23

11:59 pm-10:39 am

1 stop8h 40m

$369

PeoriaOntario

PIA - ONT

PIAONT

Greater Peoria

Tue 5/12

7:00 am-4:22 pm

2 stops11h 22m

Ontario

Sat 5/16

9:24 am-11:37 pm

2 stops12h 13m

$429

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, May 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 $98. If you aren’t able to travel during the month of May, then book flights to Ontario from Illinois during April instead. Flights to Ontario in April, while not as cheap as those in May, still average around $99.

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 $620.

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 $379. 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 afternoon when prices are $542 on average. Flights to Ontario from Illinois in the afternoon 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

Can stopping save me money on Illinois to Ontario flights?

You could potentially save up to 8% on your flight if you consider stops on a Illinois to Ontario flight.

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	$265
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 $265. The best round-trip flight deal from Illinois to Ontario found on momondo in the last 72 hours is $396.

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 April 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 30.17% of all bookings. The subsequent popular models are Airbus A321neo at 12.20%, Boeing 737-800 Passenger/BBJ2 (winglets) at 9.49%, and Boeing 737-700 at 8.14%.

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 $127	Free Cancellation	Rating 5.6 2,969 reviews	Search Frontier flights
Southwest	PriceFrom $218	Free Cancellation	Rating 8.0 4,314 reviews	Search Southwest flights
Delta	PriceFrom $256	Free Cancellation	Rating 7.9 8,463 reviews	Search Delta flights
United Airlines	PriceFrom $260	Free Cancellation	Rating 7.4 9,677 reviews	Search United Airlines flights
American Airlines	PriceFrom $294	Free Cancellation	Rating 7.1 11,681 reviews	Search American 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 $60

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 5/27. 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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Frontier flights from Illinois to Ontario

Our best Frontier deals on Illinois to Ontario flight tickets

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Our best United Airlines 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?

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 week?

How long does it take to fly 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

Fastest flight time

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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.

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

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