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

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

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 May 2026. The most frequent departure time is 11:00PM, with 53% 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.

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

Frontier, Southwest, and United Airlines 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 May 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.

$59 Cheap Flights from Ontario to Illinois in 2026

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Find the cheapest flights from Ontario to Illinois

Round-trip

One-way

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Cheap round-trip flights

Enter your travel dates to find the best prices.

11:36 am - 6:06 pm

ONT

STL

28h 30m

1 stop

8:08 pm - 10:05 am

STL

ONT

15h 57m

1 stop

$181Frontier

Mon, May 18 - Tue, May 26

10:49 am - 7:23 pm

ONT

STL

6h 34m

1 stop

8:08 pm - 11:50 pm

STL

ONT

5h 42m

1 stop

$182Frontier

Wed, Aug 12 - Sat, Aug 15

12:32 pm - 10:36 pm

ONT

MDW

8h 04m

1 stop

1:27 pm - 11:34 pm

MDW

ONT

12h 07m

2 stops

$277Delta

Sat, Aug 15 - Tue, Aug 18

6:00 am - 7:20 pm

ONT

ORD

11h 20m

2 stops

7:45 am - 12:19 pm

ORD

ONT

6h 34m

1 stop

$277Delta

Wed, May 27 - Sat, Jun 6

11:55 pm - 5:40 am

ONT

MDW

3h 45mnonstop

5:30 am - 9:35 am

MDW

ONT

6h 05m

1 stop

$283Southwest

Mon, Jun 1 - Wed, Jun 10

1:30 pm - 11:05 pm

ONT

MDW

7h 35m

1 stop

5:25 am - 9:15 am

MDW

ONT

5h 50m

1 stop

$284Southwest

Wed, Jun 24 - Tue, Jun 30

6:30 am - 4:48 pm

ONT

MLI

8h 18m

1 stop

3:47 pm - 10:51 pm

MLI

ONT

9h 04m

1 stop

$340United Airlines

Sat, May 30 - Sat, Jun 6

1:10 pm - 11:30 pm

ONT

MLI

8h 20m

2 stops

4:24 pm - 10:36 pm

MLI

ONT

8h 12m

1 stop

$345American Airlines

Sat, May 30 - Sat, Jun 6

1:10 pm - 11:30 pm

ONT

MLI

8h 20m

2 stops

11:09 am - 10:02 pm

MLI

ONT

12h 53m

2 stops

$402American Airlines

Sat, May 30 - Sat, Jun 6

6:10 am - 4:58 pm

ONT

PIA

8h 48m

1 stop

1:21 pm - 6:19 pm

PIA

ONT

6h 58m

1 stop

$449United Airlines

Wed, Aug 5 - Wed, Aug 12

Delta flights from Ontario to Illinois

Our best Delta deals on Ontario to Illinois flight tickets

Delta

May 27

ONT6:00 amOntario

11h 20m

2 stops

ORD7:20 pmChicago O'Hare Intl

Jun 6

ORD7:45 amChicago O'Hare Intl

6h 34m

1 stop

ONT12:19 pmOntario

$277

Delta

Jun 1

ONT1:29 pmOntario

6h 21m

1 stop

ORD9:50 pmChicago O'Hare Intl

Jun 3

ORD7:45 pmChicago O'Hare Intl

5h 49m

1 stop

ONT11:34 pmOntario

$282

Delta

May 26

ONT1:35 pmOntario

8h 22m

1 stop

ORD11:57 pmChicago O'Hare Intl

Jun 3

ORD2:11 pmChicago O'Hare Intl

10h 21m

2 stops

ONT10:32 pmOntario

$284

United Airlines flights from Ontario to Illinois

Our best United Airlines deals on Ontario to Illinois flight tickets

United Airlines

Jun 2

ONT1:50 pmOntario

7h 09m

1 stop

ORD10:59 pmChicago O'Hare Intl

Jun 9

ORD8:18 pmChicago O'Hare Intl

4h 33m

ONT10:51 pmOntario

$294

United Airlines

Sep 17

ONT7:00 amOntario

4h 15m

ORD1:15 pmChicago O'Hare Intl

Sep 22

ORD3:50 pmChicago O'Hare Intl

4h 29m

ONT6:19 pmOntario

$309

United Airlines

May 30

ONT6:30 amOntario

8h 18m

1 stop

MLI4:48 pmMoline Quad-City

Jun 6

MLI3:47 pmMoline Quad-City

9h 04m

1 stop

ONT10:51 pmOntario

$340

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

OntarioSt. Louis

ONT - STL

ONTSTL

Ontario

Mon 5/18

11:36 am-6:06 pm

1 stop28h 30m

Lambert-St Louis

Tue 5/26

8:08 pm-10:05 am

1 stop15h 57m

$181

OntarioSt. Louis

ONT - STL

ONTSTL

Ontario

Wed 8/12

10:49 am-7:23 pm

1 stop6h 34m

Lambert-St Louis

Sat 8/15

8:08 pm-11:50 pm

1 stop5h 42m

$182

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Sat 8/15

12:32 pm-10:36 pm

1 stop8h 04m

Chicago Midway

Tue 8/18

1:27 pm-11:34 pm

2 stops12h 07m

$277

OntarioChicago

ONT - ORD

ONTORD

Ontario

Wed 5/27

6:00 am-7:20 pm

2 stops11h 20m

Chicago O'Hare Intl

Sat 6/6

7:45 am-12:19 pm

1 stop6h 34m

$277

Quickest round-trip

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Mon 6/1

11:55 pm-5:40 am

Nonstop3h 45m

Chicago Midway

Wed 6/10

5:30 am-9:35 am

1 stop6h 05m

$283

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Wed 6/24

1:30 pm-11:05 pm

1 stop7h 35m

Chicago Midway

Tue 6/30

5:25 am-9:15 am

1 stop5h 50m

$284

OntarioMoline

ONT - MLI

ONTMLI

Ontario

Sat 5/30

6:30 am-4:48 pm

1 stop8h 18m

Moline Quad-City

Sat 6/6

3:47 pm-10:51 pm

1 stop9h 04m

$340

OntarioMoline

ONT - MLI

ONTMLI

Ontario

Sat 5/30

1:10 pm-11:30 pm

2 stops8h 20m

Moline Quad-City

Sat 6/6

4:24 pm-10:36 pm

1 stop8h 12m

$345

OntarioMoline

ONT - MLI

ONTMLI

Ontario

Sat 5/30

1:10 pm-11:30 pm

2 stops8h 20m

Moline Quad-City

Sat 6/6

11:09 am-10:02 pm

2 stops12h 53m

$402

OntarioPeoria

ONT - PIA

ONTPIA

Ontario

Wed 8/5

6:10 am-4:58 pm

1 stop8h 48m

Greater Peoria

Wed 8/12

1:21 pm-6:19 pm

1 stop6h 58m

$449

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 April. Flight prices, which tend to average around $88, 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 April, then flying in September is also cheap. Prices for this month can be found on momondo for an average of $102.

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 $444. Flights from Ontario to Illinois on a Sunday will generally be more expensive and average around $546. 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 $480. 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 $414 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 $311 on momondo.

Can stopping save me money on Ontario to Illinois flights?

No. A direct flight is the cheapest option for a flight between Ontario to Illinois.

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	$163
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 $163. The best round-trip flight deal from Ontario to Illinois found on momondo in the last 72 hours is $408.

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 May 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 17.12% of all bookings. The subsequent popular models are Boeing 737-900 at 12.53%, Airbus A321neo at 11.19%, and Airbus A320-100/200 at 8.49%.

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 2,962 reviews	Search Frontier flights
United Airlines	PriceFrom $226	Free Cancellation	Rating 7.4 9,694 reviews	Search United Airlines flights
Southwest	PriceFrom $237	Free Cancellation	Rating 7.9 4,302 reviews	Search Southwest flights
Delta	PriceFrom $260	Free Cancellation	Rating 7.9 8,456 reviews	Search Delta flights
American Airlines	PriceFrom $288	Free Cancellation	Rating 7.1 11,667 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 $54

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Flights to Chicagofrom $58

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Flights to Las Vegasfrom $46

Flights to Washington, D.C.from $56

Flights to Bostonfrom $92

Flights to Atlantafrom $56

Flights to Dallasfrom $72

Flights to Fort Lauderdalefrom $56

Cheap flights from Ontario to Illinois from $59

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 8/18. 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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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?

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

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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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