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 March 2026. The most frequent departure time is 11:00PM, with 100% of daily flights leaving in the evening.

What airlines fly to Illinois?

American Airlines, United Airlines and Spirit Airlines 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 44% of people opting to fly with this airline when traveling to Illinois. Keep in mind that there are 8 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 week?

8 flights are operational weekly from Ontario to Illinois as of March 2026. The most popular departure day for this route is Tue, with 25% of flights per week taking off on this day.

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

Frontier, Southwest, and Delta are the most popular carriers operating 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 March 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.

$79 Cheap Flights from Ontario to Illinois in 2026

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Cheap round-trip flights

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12:59 am - 7:21 pm

ONT

STL

16h 22m

1 stop

8:17 pm - 7:26 am

STL

ONT

13h 09m

1 stop

$160Frontier

qua, abr 15 - sáb, abr 18

12:59 am - 7:21 pm

ONT

STL

16h 22m

1 stop

9:55 pm - 8:24 am

STL

ONT

12h 29m

1 stop

$162Frontier

qua, abr 15 - qui, abr 23

11:55 pm - 5:40 am

ONT

MDW

3h 45mnonstop

11:00 am - 1:15 pm

MDW

ONT

4h 15mnonstop

$297Southwest

ter, abr 28 - ter, mai 5

11:55 pm - 5:40 am

ONT

MDW

3h 45mnonstop

11:00 am - 1:15 pm

MDW

ONT

4h 15mnonstop

$307Southwest

sex, abr 10 - ter, abr 14

12:57 pm - 10:31 pm

ONT

MDW

7h 34m

1 stop

1:24 pm - 9:00 pm

MDW

ONT

9h 36m

2 stops

$322Delta

qua, abr 8 - ter, abr 14

6:00 am - 5:56 pm

ONT

MDW

9h 56m

2 stops

1:22 pm - 11:34 pm

MDW

ONT

12h 12m

2 stops

$327Delta

qua, mai 20 - ter, mai 26

2:08 pm - 11:29 pm

ONT

MLI

7h 21m

1 stop

3:48 pm - 10:40 pm

MLI

ONT

8h 52m

1 stop

$369American Airlines

sex, mai 1 - qui, mai 7

12:19 pm - 11:54 pm

ONT

MLI

9h 35m

2 stops

3:48 pm - 10:40 pm

MLI

ONT

8h 52m

1 stop

$374American Airlines

sex, mai 1 - qui, mai 7

7:00 am - 4:44 pm

ONT

PIA

7h 44m

1 stop

5:35 pm - 10:31 pm

PIA

ONT

6h 56m

1 stop

$419United Airlines

qua, abr 8 - dom, abr 12

1:34 pm - 9:32 pm

ONT

MLI

5h 58m

1 stop

5:49 pm - 10:31 pm

MLI

ONT

6h 42m

1 stop

$469United Airlines

ter, abr 14 - sáb, abr 18

Frontier flights from Ontario to Illinois

Our best Frontier deals on Ontario to Illinois flight tickets

Frontier

Apr 15

ONT12:59 amOntario

16h 22m

1 stop

STL7:21 pmLambert-St Louis

Apr 18

STL8:17 pmLambert-St Louis

13h 09m

1 stop

ONT7:26 amOntario

$160

Frontier

Apr 15

ONT12:59 amOntario

16h 22m

1 stop

STL7:21 pmLambert-St Louis

Apr 23

STL9:55 pmLambert-St Louis

12h 29m

1 stop

ONT8:24 amOntario

$162

Frontier

Apr 17

ONT5:33 pmOntario

23h 59m

1 stop

STL7:32 pmLambert-St Louis

Apr 24

STL9:58 pmLambert-St Louis

22h 51m

1 stop

ONT6:49 pmOntario

$166

Delta flights from Ontario to Illinois

Our best Delta deals on Ontario to Illinois flight tickets

Delta

Apr 8

ONT12:57 pmOntario

7h 34m

1 stop

MDW10:31 pmChicago Midway

Apr 14

MDW1:24 pmChicago Midway

9h 36m

2 stops

ONT9:00 pmOntario

$322

Delta

May 20

ONT6:00 amOntario

9h 56m

2 stops

MDW5:56 pmChicago Midway

May 26

MDW1:22 pmChicago Midway

12h 12m

2 stops

ONT11:34 pmOntario

$327

Delta

Apr 18

ONT7:05 amOntario

7h 21m

1 stop

MDW4:26 pmChicago Midway

Apr 25

MDW6:00 amChicago Midway

7h 36m

1 stop

ONT11:36 amOntario

$337

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

OntarioSt. Louis

ONT - STL

ONTSTL

Ontario

qua 4/15

12:59 am-7:21 pm

1 stop16h 22m

Lambert-St Louis

sáb 4/18

8:17 pm-7:26 am

1 stop13h 09m

$160

OntarioSt. Louis

ONT - STL

ONTSTL

Ontario

qua 4/15

12:59 am-7:21 pm

1 stop16h 22m

Lambert-St Louis

qui 4/23

9:55 pm-8:24 am

1 stop12h 29m

$162

Quickest round-trip

OntarioChicago

ONT - MDW

ONTMDW

Ontario

ter 4/28

11:55 pm-5:40 am

Nonstop3h 45m

Chicago Midway

ter 5/5

11:00 am-1:15 pm

Nonstop4h 15m

$297

OntarioChicago

ONT - MDW

ONTMDW

Ontario

sex 4/10

11:55 pm-5:40 am

Nonstop3h 45m

Chicago Midway

ter 4/14

11:00 am-1:15 pm

Nonstop4h 15m

$307

OntarioChicago

ONT - MDW

ONTMDW

Ontario

qua 4/8

12:57 pm-10:31 pm

1 stop7h 34m

Chicago Midway

ter 4/14

1:24 pm-9:00 pm

2 stops9h 36m

$322

OntarioChicago

ONT - MDW

ONTMDW

Ontario

qua 5/20

6:00 am-5:56 pm

2 stops9h 56m

Chicago Midway

ter 5/26

1:22 pm-11:34 pm

2 stops12h 12m

$327

OntarioMoline

ONT - MLI

ONTMLI

Ontario

sex 5/1

2:08 pm-11:29 pm

1 stop7h 21m

Moline Quad-City

qui 5/7

3:48 pm-10:40 pm

1 stop8h 52m

$369

OntarioMoline

ONT - MLI

ONTMLI

Ontario

sex 5/1

12:19 pm-11:54 pm

2 stops9h 35m

Moline Quad-City

qui 5/7

3:48 pm-10:40 pm

1 stop8h 52m

$374

OntarioPeoria

ONT - PIA

ONTPIA

Ontario

qua 4/8

7:00 am-4:44 pm

1 stop7h 44m

Greater Peoria

dom 4/12

5:35 pm-10:31 pm

1 stop6h 56m

$419

OntarioMoline

ONT - MLI

ONTMLI

Ontario

ter 4/14

1:34 pm-9:32 pm

1 stop5h 58m

Moline Quad-City

sáb 4/18

5:49 pm-10:31 pm

1 stop6h 42m

$469

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 January. Flight prices, which tend to average around $307, 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 January, then flying in June is also cheap. Prices for this month can be found on momondo for an average of $317.

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

The cheapest day to depart from Ontario to Illinois is on a Thursday when prices can be found for as low as $430. Flights from Ontario to Illinois on a Sunday will generally be more expensive and average around $513. 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 morning. Flights from Ontario to Illinois during this time can be as low as $453. 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 O'Hare Intl for the best Ontario - Illinois flight prices

How far in advance should I book a flight 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 $395 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 $297 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 42% 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	$223
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 $223. The best round-trip flight deal from Ontario to Illinois found on momondo in the last 72 hours is $354.

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

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 March 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 MAX 8, representing 16.39% of all bookings. The subsequent popular models are Airbus A321neo at 13.44%, Boeing 737-800 Passenger/BBJ2 (winglets) at 9.39%, and Boeing 737-900 at 7.00%.

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 $98	Free Cancellation	Rating 5.7 3,018 reviews	Search Frontier flights
United Airlines	PriceFrom $226	Free Cancellation	Rating 7.4 9,469 reviews	Search United Airlines flights
Southwest	PriceFrom $237	Free Cancellation	Rating 8.0 4,331 reviews	Search Southwest flights
American Airlines	PriceFrom $246	Free Cancellation	Rating 7.1 11,491 reviews	Search American Airlines flights
Delta	PriceFrom $256	Free Cancellation	Rating 7.9 8,320 reviews	Search Delta 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 $66

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Flights to Chicagofrom $66

Flights to San Franciscofrom $84

Flights to Las Vegasfrom $57

Flights to Washington, D.C.from $59

Flights to Bostonfrom $70

Flights to Atlantafrom $49

Flights to Dallasfrom $60

Flights to Seattlefrom $71

Cheap flights from Ontario to Illinois from $79

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 5/1. 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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Our best Frontier deals on Ontario to Illinois flight tickets

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Our best Delta 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 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

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

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

Ontario flight routes

According to popular flight searches on momondo this year

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