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 Peoria to Los Angeles is 6h 25m on average. Los Angeles is the most popular airport in Ontario.

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

Frontier is the most popular carrier operating from Illinois to Ontario

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

14 flights are operational weekly from Illinois to Ontario as of September 2025. The most popular departure day for this route is Mon, with 29% of flights per week taking off on this day.

What airlines fly to Ontario?

American Airlines, Spirit Airlines and United Airlines 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 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 day?

As of September 2025, 2 flights take off from Illinois and land in Ontario each day. The most common flight departure time for this route is 7:00PM, with 66% of daily flights taking off in the evening.

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 2025, 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.

$72 Cheap Flights from Illinois to Ontario in 2025/26

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Find the cheapest flights from Illinois to Los Angeles

Round-trip

One-way

Last minute

Direct

Cheap round-trip flights

7:52 pm - 9:35 amSTL-ONT

15h 43m1 stop

6:53 am - 9:07 amONT-STL

24h 14m1 stop

$142Frontier

Find Deal

Thu, Oct 16 - Wed, Oct 22

9:59 pm - 12:37 pmSTL-ONT

16h 38m1 stop

6:53 am - 9:07 amONT-STL

24h 14m1 stop

$143Frontier

Find Deal

Fri, Oct 10 - Sun, Oct 12

6:33 am - 12:37 pmSTL-ONT

8h 04m1 stop

6:53 am - 9:07 amONT-STL

24h 14m1 stop

$222Multiple Airlines

Find Deal

Wed, Oct 22 - Sun, Oct 26

7:25 am - 10:05 pmORD-ONT

16h 40m2 stops

12:49 pm - 12:26 amONT-ORD

9h 37m1 stop

$231Multiple Airlines

Find Deal

Fri, Oct 24 - Sun, Oct 26

4:51 pm - 10:42 pmPIA-ONT

7h 51m1 stop

12:46 pm - 11:06 pmONT-PIA

8h 20m1 stop

$289American Airlines

Find Deal

Tue, Oct 28 - Wed, Nov 5

3:45 pm - 10:26 pmMLI-ONT

8h 41m1 stop

7:00 am - 4:54 pmONT-MLI

7h 54m1 stop

$289United Airlines

Find Deal

Sat, Jan 17 - Sat, Jan 24

3:57 pm - 12:03 amSTL-ONT

10h 06m1 stop

1:31 pm - 12:03 amONT-STL

8h 32m1 stop

$292Alaska Airlines

Find Deal

Wed, Oct 15 - Fri, Oct 17

6:36 am - 3:24 pmPIA-ONT

10h 48m2 stops

12:46 pm - 11:06 pmONT-PIA

8h 20m1 stop

$294American Airlines

Find Deal

Tue, Oct 28 - Wed, Nov 5

3:45 pm - 10:26 pmMLI-ONT

8h 41m1 stop

6:39 pm - 10:12 amONT-MLI

13h 33m2 stops

$294United Airlines

Find Deal

Sat, Jan 17 - Sat, Jan 24

3:23 pm - 11:29 pmSTL-ONT

10h 06m1 stop

12:13 pm - 11:59 pmONT-STL

9h 46m1 stop

$337Alaska Airlines

Find Deal

Fri, Dec 5 - Mon, Dec 8

Frontier flights from Illinois to Ontario

Our best Frontier deals on Illinois to Ontario flight tickets

Frontier

Oct 16

STL7:52 pmLambert-St Louis

15h 43m

1 stop

ONT9:35 amOntario

Oct 22

ONT6:53 amOntario

24h 14m

1 stop

STL9:07 amLambert-St Louis

$142

Find similar

Frontier

Oct 10

STL9:59 pmLambert-St Louis

16h 38m

1 stop

ONT12:37 pmOntario

Oct 12

ONT6:53 amOntario

24h 14m

1 stop

STL9:07 amLambert-St Louis

$143

Find similar

Frontier

Oct 16

STL7:52 pmLambert-St Louis

15h 43m

1 stop

ONT9:35 amOntario

Oct 19

ONT6:53 amOntario

24h 14m

1 stop

STL9:07 amLambert-St Louis

$144

Find similar

American Airlines flights from Illinois to Ontario

Our best American Airlines deals on Illinois to Ontario flight tickets

American Airlines

Oct 28

PIA4:51 pmGreater Peoria

7h 51m

1 stop

ONT10:42 pmOntario

Nov 5

ONT12:46 pmOntario

8h 20m

1 stop

PIA11:06 pmGreater Peoria

$289

Find similar

American Airlines

Oct 28

PIA6:36 amGreater Peoria

10h 48m

2 stops

ONT3:24 pmOntario

Nov 5

ONT12:46 pmOntario

8h 20m

1 stop

PIA11:06 pmGreater Peoria

$294

Find similar

American Airlines

Dec 9

STL9:30 amLambert-St Louis

8h 31m

2 stops

ONT4:01 pmOntario

Dec 13

ONT4:47 pmOntario

5h 09m

1 stop

STL11:56 pmLambert-St Louis

$298

Find similar

Fly from

Fly to

Route

Depart

Return

Price

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Thu 10/16

7:52 pm-9:35 am

1 stop15h 43m

Ontario

Wed 10/22

6:53 am-9:07 am

1 stop24h 14m

$142

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Fri 10/10

9:59 pm-12:37 pm

1 stop16h 38m

Ontario

Sun 10/12

6:53 am-9:07 am

1 stop24h 14m

$143

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Wed 10/22

6:33 am-12:37 pm

1 stop8h 04m

Ontario

Sun 10/26

6:53 am-9:07 am

1 stop24h 14m

$222

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Fri 10/24

7:25 am-10:05 pm

2 stops16h 40m

Ontario

Sun 10/26

12:49 pm-12:26 am

1 stop9h 37m

$231

PeoriaOntario

PIA - ONT

PIAONT

Greater Peoria

Tue 10/28

4:51 pm-10:42 pm

1 stop7h 51m

Ontario

Wed 11/5

12:46 pm-11:06 pm

1 stop8h 20m

$289

MolineOntario

MLI - ONT

MLIONT

Moline Quad-City

Sat 1/17

3:45 pm-10:26 pm

1 stop8h 41m

Ontario

Sat 1/24

7:00 am-4:54 pm

1 stop7h 54m

$289

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Wed 10/15

3:57 pm-12:03 am

1 stop10h 06m

Ontario

Fri 10/17

1:31 pm-12:03 am

1 stop8h 32m

$292

PeoriaOntario

PIA - ONT

PIAONT

Greater Peoria

Tue 10/28

6:36 am-3:24 pm

2 stops10h 48m

Ontario

Wed 11/5

12:46 pm-11:06 pm

1 stop8h 20m

$294

MolineOntario

MLI - ONT

MLIONT

Moline Quad-City

Sat 1/17

3:45 pm-10:26 pm

1 stop8h 41m

Ontario

Sat 1/24

6:39 pm-10:12 am

2 stops13h 33m

$294

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Fri 12/5

3:23 pm-11:29 pm

1 stop10h 06m

Ontario

Mon 12/8

12:13 pm-11:59 pm

1 stop9h 46m

$337

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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, November 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 $158. If you aren’t able to travel during the month of November, then book flights to Ontario from Illinois during October instead. Flights to Ontario in October, while not as cheap as those in November, still average around $245.

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 Tuesday when prices can be found for as low as $330. 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 $485.

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

In the evening is the cheapest time of day to fly from Illinois to Ontario when you can find flight prices for as low as $343. Flying to Ontario in the evening 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 $462 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

How far in advance should I book a flight to Ontario?

You are more likely to see cheaper flights to Ontario from Illinois when booking weeks ahead of your departure date. In general, you can expect to find flights to Ontario for around $338 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Ontario from Illinois for as low as $273 on momondo.

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?

You could potentially save up to 24% 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	$176
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 $176. The best round-trip flight deal from Illinois to Ontario found on momondo in the last 72 hours is $263.

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

Direct flights go from Illinois to Ontario every day.

There is 1 airport near Ontario: Ontario (ONT)

Search flight deals

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 2025, 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 737-800, representing 26.77% of all bookings. The subsequent popular models are Airbus A320neo at 12.12%, Boeing 737-700 Passenger/BBJ1 (winglets) at 10.10%, and Boeing 737 MAX 8 at 9.60%.

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 $126	Free Cancellation	Rating 5.8 3,163 reviews	Search Frontier flights
American Airlines	PriceFrom $231	Free Cancellation	Rating 7.2 10,000 reviews	Search American Airlines flights
United Airlines	PriceFrom $237	Free Cancellation	Rating 7.4 8,928 reviews	Search United Airlines flights
Southwest	PriceFrom $246	Free Cancellation	Rating 8.0 4,244 reviews	Search Southwest flights
Delta	PriceFrom $256	Free Cancellation	Rating 7.9 7,973 reviews	Search Delta 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.

An easier way to manage your Ontario trip

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Cheap flights from Illinois to Los Angeles from $72

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 11/8. 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 American Airlines 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

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

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?

Fly from Chicago O'Hare Intl to Ontario for the best Illinois - Ontario flight prices

How far in advance should I book a flight to Ontario?

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?

You could potentially save up to 24% on your flight if you consider stops on a Illinois to Ontario flight.

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

Frontier is the most popular carrier operating from Illinois to Ontario

What airlines fly to Ontario?

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

As of September 2025, 2 flights take off from Illinois and land in Ontario each day. The most common flight departure time for this route is 7:00PM, with 66% of daily flights taking off in the evening.

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

14 flights are operational weekly from Illinois to Ontario as of September 2025. The most popular departure day for this route is Mon, with 29% of flights per week taking off on this day.

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 Peoria to Los Angeles is 6h 25m on average. Los Angeles is the most popular airport in 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

Direct flights

Airports in Ontario

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

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

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

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

What is the most popular plane model 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?

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

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

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

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

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

Airports servicing California