What airlines fly to Illinois?

American Airlines, United Airlines and Frontier are the top three most popular airlines that fly to Illinois from Ontario according to our data. American Airlines is the first choice among our users, with 45% of people opting to fly with this airline when traveling to Illinois. Keep in mind that there are 7 different airlines that fly to Illinois on a routine basis, so you have a few additional options to choose from.

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

The number of flights available between Ontario and Illinois is 1 per day as of June 2026. The most frequent departure time is 11:00PM, with 53% of daily flights leaving in the evening.

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

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

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

10 flights are operational weekly from Ontario to Illinois as of June 2026. The most popular departure day for this route is Mon, with 20% of flights per week taking off on this day.

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

Prices for flights from Ontario Airport to Illinois were last updated today.

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

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

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

The minimum age for a child to fly alone is five, but airlines offering an unaccompanied minor (UNMR) service may have their age restrictions, such as regulations concerning flight duration, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Ontario Airport to Illinois.

What documentation or ID do you need to fly to Illinois?

The travel and health documents required for your trip to Illinois 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 Illinois. We always recommend checking with your airline or a trusted third party such as IATA to get advice.

$108 Cheap Flights from Ontario to Illinois in 2026

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Find the cheapest flights from Ontario to Illinois

Round-trip

One-way

Last minute

Direct

Cheap round-trip flights

Enter your travel dates to find the best prices.

3:40 pm - 6:05 pm

ONT

STL

24h 25m

1 stop

8:08 pm - 10:04 am

STL

ONT

15h 56m

1 stop

$199Frontier

Tue, Jul 14 - Tue, Jul 21

6:00 am - 7:23 pm

ONT

STL

11h 23m

1 stop

7:10 pm - 3:54 pm

STL

ONT

22h 44m

1 stop

$223Frontier

Tue, Aug 4 - Sun, Aug 9

7:00 am - 1:10 pm

ONT

ORD

4h 10mnonstop

8:06 pm - 10:35 pm

ORD

ONT

4h 29mnonstop

$298United Airlines

Thu, Aug 13 - Wed, Aug 19

1:56 pm - 12:59 am

ONT

ORD

9h 03m

1 stop

8:06 pm - 10:35 pm

ORD

ONT

4h 29mnonstop

$306United Airlines

Mon, Aug 17 - Wed, Aug 19

11:55 pm - 5:45 am

ONT

MDW

3h 50mnonstop

6:15 pm - 10:05 pm

MDW

ONT

5h 50m

1 stop

$307Southwest

Tue, Aug 4 - Thu, Aug 6

8:10 pm - 5:45 am

ONT

MDW

7h 35m

1 stop

5:40 am - 9:20 am

MDW

ONT

5h 40m

1 stop

$317Southwest

Thu, Aug 13 - Mon, Aug 17

6:00 am - 6:18 pm

ONT

MDW

10h 18m

2 stops

11:05 am - 6:30 pm

MDW

ONT

9h 25m

1 stop

$324Delta

Tue, Jul 14 - Wed, Jul 22

6:20 am - 6:33 pm

ONT

MDW

10h 13m

2 stops

9:59 am - 4:24 pm

MDW

ONT

8h 25m

2 stops

$329Delta

Thu, Aug 27 - Tue, Sep 1

12:59 pm - 12:08 am

ONT

MLI

9h 09m

2 stops

7:33 am - 1:31 pm

MLI

ONT

7h 58m

1 stop

$345American Airlines

Wed, Aug 19 - Sun, Aug 23

1:11 pm - 11:30 pm

ONT

MLI

8h 19m

2 stops

11:09 am - 9:43 pm

MLI

ONT

12h 34m

2 stops

$414American Airlines

Wed, Jul 8 - Tue, Jul 28

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Delta flights from Ontario to Illinois

Our best Delta deals on Ontario to Illinois flight tickets

Delta

Aug 31

ONT6:01 pmOntario

12h 29m

2 stops

ORD8:30 amChicago O'Hare Intl

Sep 5

ORD6:00 amChicago O'Hare Intl

8h 16m

2 stops

ONT12:16 pmOntario

$298

Delta

Aug 8

ONT1:06 pmOntario

6h 24m

1 stop

ORD9:30 pmChicago O'Hare Intl

Aug 22

ORD7:48 amChicago O'Hare Intl

6h 28m

1 stop

ONT12:16 pmOntario

$317

Delta

Jul 14

ONT9:40 amOntario

7h 17m

1 stop

ORD6:57 pmChicago O'Hare Intl

Jul 28

ORD7:40 pmChicago O'Hare Intl

6h 08m

1 stop

ONT11:48 pmOntario

$319

United Airlines flights from Ontario to Illinois

Our best United Airlines deals on Ontario to Illinois flight tickets

United Airlines

Aug 17

ONT1:56 pmOntario

9h 03m

1 stop

ORD12:59 amChicago O'Hare Intl

Aug 19

ORD8:06 pmChicago O'Hare Intl

4h 29m

ONT10:35 pmOntario

$306

United Airlines

Aug 20

ONT7:13 pmOntario

8h 46m

1 stop

ORD5:59 amChicago O'Hare Intl

Aug 24

ORD8:06 pmChicago O'Hare Intl

4h 29m

ONT10:35 pmOntario

$307

United Airlines

Aug 1

ONT6:10 amOntario

4h 15m

ORD12:25 pmChicago O'Hare Intl

Aug 4

ORD8:18 pmChicago O'Hare Intl

4h 33m

ONT10:51 pmOntario

$311

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

OntarioSt. Louis

ONT - STL

ONTSTL

Ontario

Tue 7/14

3:40 pm-6:05 pm

1 stop24h 25m

Lambert-St Louis

Tue 7/21

8:08 pm-10:04 am

1 stop15h 56m

$199

OntarioSt. Louis

ONT - STL

ONTSTL

Ontario

Tue 8/4

6:00 am-7:23 pm

1 stop11h 23m

Lambert-St Louis

Sun 8/9

7:10 pm-3:54 pm

1 stop22h 44m

$223

Quickest round-trip

OntarioChicago

ONT - ORD

ONTORD

Ontario

Thu 8/13

7:00 am-1:10 pm

Nonstop4h 10m

Chicago O'Hare Intl

Wed 8/19

8:06 pm-10:35 pm

Nonstop4h 29m

$298

OntarioChicago

ONT - ORD

ONTORD

Ontario

Mon 8/17

1:56 pm-12:59 am

1 stop9h 03m

Chicago O'Hare Intl

Wed 8/19

8:06 pm-10:35 pm

Nonstop4h 29m

$306

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Tue 8/4

11:55 pm-5:45 am

Nonstop3h 50m

Chicago Midway

Thu 8/6

6:15 pm-10:05 pm

1 stop5h 50m

$307

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Thu 8/13

8:10 pm-5:45 am

1 stop7h 35m

Chicago Midway

Mon 8/17

5:40 am-9:20 am

1 stop5h 40m

$317

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Tue 7/14

6:00 am-6:18 pm

2 stops10h 18m

Chicago Midway

Wed 7/22

11:05 am-6:30 pm

1 stop9h 25m

$324

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Thu 8/27

6:20 am-6:33 pm

2 stops10h 13m

Chicago Midway

Tue 9/1

9:59 am-4:24 pm

2 stops8h 25m

$329

OntarioMoline

ONT - MLI

ONTMLI

Ontario

Wed 8/19

12:59 pm-12:08 am

2 stops9h 09m

Moline Quad-City

Sun 8/23

7:33 am-1:31 pm

1 stop7h 58m

$345

OntarioMoline

ONT - MLI

ONTMLI

Ontario

Wed 7/8

1:11 pm-11:30 pm

2 stops8h 19m

Moline Quad-City

Tue 7/28

11:09 am-9:43 pm

2 stops12h 34m

$414

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 Ontario to Illinois

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 Illinois?

The cheapest month to fly to Illinois from Ontario is in September. Flight prices, which tend to average around $102, are often lower during this time because this is during the off-season. If you aren’t able to travel to Illinois during the month of September, then flying in April is also cheap. Prices for this month can be found on momondo for an average of $108.

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

The cheapest day to depart from Ontario to Illinois is on a Wednesday when prices can be found for as low as $452. Flights from Ontario to Illinois on a Sunday will generally be more expensive and average around $547. Keep in mind that these prices on both days could fluctuate depending on the season and the demand.

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

Our most recent data shows that the best time of day to fly to Illinois is in the evening. Flights from Ontario to Illinois during this time can be as low as $482. Flights at noon are often more expensive with an average ticket price of $526.

What is the cheapest Ontario to Illinois flight route?

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

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

You are more likely to see cheaper flights to Illinois from Ontario when booking weeks ahead of your departure date. In general, you can expect to find flights to Illinois for around $427 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Illinois from Ontario for as low as $345 on momondo.

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

There are 4 cabin classes available to choose from on Ontario to Illinois 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 Ontario to Illinois flights?

You could potentially save up to 16% on your flight if you consider stops on a Ontario to Illinois flight.

Cheap Ontario to Illinois flight deals and tips

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

Best Price Found	$218
Fastest flight time	3h 45m
Direct flights	Every day
Airports in Illinois	98 airports

The best one-way flight to Illinois from Ontario in the past 72 hours is $218. The best round-trip flight deal from Ontario to Illinois found on momondo in the last 72 hours is $420.

The fastest flight from Ontario to Illinois takes 3h 45m

Direct flights go from Ontario to Illinois every day.

There are 98 airports in Illinois. From Ontario there are direct flights to Chicago O'Hare Intl (ORD), Chicago Midway (MDW).

Search flight deals

Frequently asked questions about flying from Ontario to Illinois

When did momondo last update prices for flights from Ontario Airport to Illinois?
Prices for flights from Ontario Airport to Illinois were last updated today.
How many operators does momondo search for flights from Ontario Airport to Illinois?
As of June 2026, there are 5 operators available to choose from for flights from Ontario Airport to Illinois.
How old do you have to be to fly from Ontario Airport to Illinois?
The minimum age for a child to fly alone is five, but airlines offering an unaccompanied minor (UNMR) service may have their age restrictions, such as regulations concerning flight duration, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Ontario Airport to Illinois.
What documentation or ID do you need to fly to Illinois?
The travel and health documents required for your trip to Illinois 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 Illinois. 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 Ontario to Illinois?
momondo data reveals that the most frequently booked plane model on the route from Ontario to Illinois is Boeing 737-900, representing 19.52% of all bookings. The subsequent popular models are Boeing 737 MAX 8 at 19.41%, Airbus A321neo at 10.22%, and Airbus A320-100/200 at 7.60%.

Best airlines flying from Ontario to Illinois

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

Airline	Rating	Free Cancellation	Price
Frontier	PriceFrom $117	Free Cancellation	Rating 5.6 2,870 reviews	Search Frontier flights
United Airlines	PriceFrom $255	Free Cancellation	Rating 7.4 9,875 reviews	Search United Airlines flights
Southwest	PriceFrom $258	Free Cancellation	Rating 7.9 4,243 reviews	Search Southwest flights
Delta	PriceFrom $260	Free Cancellation	Rating 7.8 8,421 reviews	Search Delta flights
American Airlines	PriceFrom $288	Free Cancellation	Rating 7.1 11,739 reviews	Search American Airlines flights

Why use momondo?

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

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

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

Flights from Ontario to Illinois with flexible booking policies can be found by using the search form above and then selecting our dedicated flexible booking filter, which will highlight only the flights where this policy is applied.

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

Once you have performed a search for Ontario to Illinois flights, momondo helps you find the right one by offering useful filters to narrow down your flight selection. Flights can be filtered by multiple factors such as airline, airport and price; but also by other criteria like aircraft type and payment method.

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

If you are simply researching potential flights to Illinois, momondo offers a useful price alert feature which will track prices for flights to Illinois from Ontario and alert you when they change.

An easier way to manage your Illinois trip

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Popular cities in Illinois

Flights to New Yorkfrom $62

Flights to Los Angelesfrom $56

Flights to Orlandofrom $63

Flights to Miamifrom $78

Flights to Chicagofrom $74

Flights to San Franciscofrom $50

Flights to Las Vegasfrom $56

Flights to Washington, D.C.from $57

Flights to Bostonfrom $54

Flights to Atlantafrom $58

Flights to Fort Lauderdalefrom $59

Flights to Dallasfrom $72

Cheap flights from Ontario to Illinois from $108

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Ontario to Illinois departing on 7/21. 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 Ontario to Illinois

Our best Delta deals on Ontario to Illinois flight tickets

United Airlines flights from Ontario to Illinois

Our best United Airlines deals on Ontario to Illinois flight tickets

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See travel insights to Illinois from

How to get the cheapest flight ticket from Ontario to Illinois

What is the cheapest month to fly to Illinois?

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

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

What is the cheapest Ontario to Illinois flight route?

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

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

Can stopping save me money on Ontario to Illinois flights?

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

What airlines fly to Illinois?

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

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

Cheap Ontario to Illinois flight deals and tips

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

Best Price Found

Fastest flight time

Direct flights

Airports in Illinois

Frequently asked questions about flying from Ontario to Illinois

Best airlines flying from Ontario to Illinois

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

Why use momondo?

An easier way to manage your Illinois 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 Illinois

Popular cities in Illinois

Popular flights according to clicks in the last 7 days on momondo

Ontario flight routes

According to popular flight searches on momondo this year

Illinois flight routes

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