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 45% 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 day?

The number of flights available between Ontario and Illinois is 2 per day as of November 2025. The most frequent departure time is 7:00AM, with 100% of daily flights leaving at noon.

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

Frontier, Alaska 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?

14 flights are operational weekly from Ontario to Illinois as of November 2025. The most popular departure day for this route is Mon, with 29% 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 November 2025, 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.

$61 Cheap Flights from Ontario to Illinois in 2025/26

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One-way

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Cheap round-trip flights

Enter your travel dates to find the best prices.

6:15 am - 12:12 pmONT-STL

27h 57m1 stop

10:10 pm - 3:09 pmSTL-ONT

18h 59m1 stop

$182Frontier

Find Deal

jue., dic. 11 - lun., ene. 5

6:00 am - 6:45 pmONT-ORD

10h 45m1 stop

10:41 pm - 7:37 amORD-ONT

10h 56m1 stop

$182Frontier

Find Deal

lun., ene. 12 - jue., ene. 15

11:59 pm - 10:39 amONT-PIA

8h 40m1 stop

11:15 am - 6:45 pmPIA-ONT

9h 30m1 stop

$324American Airlines

Find Deal

jue., ene. 8 - dom., ene. 11

9:59 am - 11:24 pmONT-PIA

11h 25m2 stops

11:15 am - 6:45 pmPIA-ONT

9h 30m1 stop

$329American Airlines

Find Deal

jue., ene. 8 - dom., ene. 11

7:00 am - 4:31 pmONT-PIA

7h 31m1 stop

5:20 pm - 10:26 pmPIA-ONT

7h 06m1 stop

$379United Airlines

Find Deal

mié., may. 13 - mié., may. 20

12:41 pm - 10:08 pmONT-BMI

7h 27m1 stop

3:35 pm - 9:05 pmBMI-ONT

7h 30m1 stop

$379Delta

Find Deal

mar., ene. 27 - sáb., ene. 31

1:24 pm - 8:34 pmONT-MLI

5h 10m1 stop

10:47 am - 8:58 pmMLI-ONT

12h 11m2 stops

$384United Airlines

Find Deal

mar., ene. 20 - sáb., ene. 24

6:15 am - 12:30 pmONT-RFD

28h 15m1 stop

1:20 pm - 9:17 pmRFD-ONT

9h 57m1 stop

$437Multiple Airlines

Find Deal

mié., dic. 10 - dom., dic. 14

6:15 am - 12:30 pmONT-RFD

28h 15m1 stop

1:20 pm - 11:31 pmRFD-ONT

36h 11m2 stops

$442Multiple Airlines

Find Deal

mié., dic. 10 - dom., dic. 14

12:41 pm - 10:22 pmONT-EVV

7h 41m1 stop

1:00 pm - 9:05 pmEVV-ONT

10h 05m1 stop

$490Delta

Find Deal

mié., ene. 28 - sáb., ene. 31

Frontier flights from Ontario to Illinois

Our best Frontier deals on Ontario to Illinois flight tickets

Frontier

Jan 12

ONT6:00 amOntario

10h 45m

1 stop

ORD6:45 pmChicago O'Hare Intl

Jan 15

ORD10:41 pmChicago O'Hare Intl

10h 56m

1 stop

ONT7:37 amOntario

$182

Find similar

Frontier

Dec 23

ONT6:45 amOntario

25h 17m

1 stop

STL10:02 amLambert-St Louis

Dec 28

STL10:10 pmLambert-St Louis

21h 05m

1 stop

ONT5:15 pmOntario

$183

Find similar

Frontier

Dec 23

ONT6:00 amOntario

6h 17m

1 stop

ORD2:17 pmChicago O'Hare Intl

Jan 4

ORD10:49 pmChicago O'Hare Intl

20h 26m

1 stop

ONT5:15 pmOntario

$184

Find similar

Delta flights from Ontario to Illinois

Our best Delta deals on Ontario to Illinois flight tickets

Delta

Dec 15

ONT6:00 amOntario

5h 30m

1 stop

STL1:30 pmLambert-St Louis

Dec 16

STL6:30 amLambert-St Louis

12h 37m

2 stops

ONT5:07 pmOntario

$331

Find similar

Delta

Feb 23

ONT10:20 pmOntario

9h 36m

1 stop

MDW9:56 amChicago Midway

Feb 28

MDW1:28 pmChicago Midway

11h 09m

2 stops

ONT10:37 pmOntario

$345

Find similar

Delta

Dec 15

ONT6:00 amOntario

5h 30m

1 stop

STL1:30 pmLambert-St Louis

Dec 16

STL11:40 amLambert-St Louis

9h 59m

1 stop

ONT7:39 pmOntario

$347

Find similar

Fly from

Fly to

Route

Depart

Return

Price

OntarioSt. Louis

ONT - STL

ONTSTL

Ontario

jue. 12/11

6:15 am-12:12 pm

1 stop27h 57m

Lambert-St Louis

lun. 1/5

10:10 pm-3:09 pm

1 stop18h 59m

$182

OntarioChicago

ONT - ORD

ONTORD

Ontario

lun. 1/12

6:00 am-6:45 pm

1 stop10h 45m

Chicago O'Hare Intl

jue. 1/15

10:41 pm-7:37 am

1 stop10h 56m

$182

OntarioPeoria

ONT - PIA

ONTPIA

Ontario

jue. 1/8

11:59 pm-10:39 am

1 stop8h 40m

Greater Peoria

dom. 1/11

11:15 am-6:45 pm

1 stop9h 30m

$324

OntarioPeoria

ONT - PIA

ONTPIA

Ontario

jue. 1/8

9:59 am-11:24 pm

2 stops11h 25m

Greater Peoria

dom. 1/11

11:15 am-6:45 pm

1 stop9h 30m

$329

OntarioPeoria

ONT - PIA

ONTPIA

Ontario

mié. 5/13

7:00 am-4:31 pm

1 stop7h 31m

Greater Peoria

mié. 5/20

5:20 pm-10:26 pm

1 stop7h 06m

$379

OntarioBloomington

ONT - BMI

ONTBMI

Ontario

mar. 1/27

12:41 pm-10:08 pm

1 stop7h 27m

Bloomington-Normal

sáb. 1/31

3:35 pm-9:05 pm

1 stop7h 30m

$379

OntarioMoline

ONT - MLI

ONTMLI

Ontario

mar. 1/20

1:24 pm-8:34 pm

1 stop5h 10m

Moline Quad-City

sáb. 1/24

10:47 am-8:58 pm

2 stops12h 11m

$384

OntarioChicago

ONT - RFD

ONTRFD

Ontario

mié. 12/10

6:15 am-12:30 pm

1 stop28h 15m

Chicago Greater Rockford

dom. 12/14

1:20 pm-9:17 pm

1 stop9h 57m

$437

OntarioChicago

ONT - RFD

ONTRFD

Ontario

mié. 12/10

6:15 am-12:30 pm

1 stop28h 15m

Chicago Greater Rockford

dom. 12/14

1:20 pm-11:31 pm

2 stops36h 11m

$442

OntarioEvansville

ONT - EVV

ONTEVV

Ontario

mié. 1/28

12:41 pm-10:22 pm

1 stop7h 41m

Evansville Dress Regional

sáb. 1/31

1:00 pm-9:05 pm

1 stop10h 05m

$490

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 November. Flight prices, which tend to average around $310, 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 November, 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 Tuesday when prices can be found for as low as $440. Flights from Ontario to Illinois on a Sunday will generally be more expensive and average around $501. 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 afternoon. Flights from Ontario to Illinois during this time can be as low as $276. Flights in the evening are often more expensive with an average ticket price of $584.

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 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 $391 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 $296 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?

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	$167
Fastest flight time	3h 45m
Direct flights	Every day
Airports in Illinois	2 airports

The best one-way flight to Illinois from Ontario in the past 72 hours is $167. The best round-trip flight deal from Ontario to Illinois found on momondo in the last 72 hours is $376.

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

Direct flights go from Ontario to Illinois every day.

There are 2 airports near Illinois: 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 November 2025, 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 Airbus A321neo, representing 17.86% of all bookings. The subsequent popular models are Boeing 737-800 at 15.61%, Airbus A318/A319/A320/A321 at 7.59%, and Boeing 737 MAX 8 at 7.03%.

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 $110	Free Cancellation	Rating 5.8 3,099 reviews	Search Frontier flights
United Airlines	PriceFrom $227	Free Cancellation	Rating 7.4 9,046 reviews	Search United Airlines flights
Southwest	PriceFrom $237	Free Cancellation	Rating 8.0 4,254 reviews	Search Southwest flights
American Airlines	PriceFrom $246	Free Cancellation	Rating 7.2 11,038 reviews	Search American Airlines flights
Delta	PriceFrom $256	Free Cancellation	Rating 7.9 7,999 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

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.

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Find better results for your trip to Illinois

Popular cities in Illinois

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Flights to Washington, D.C.from $38

Flights to Bostonfrom $59

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Flights to Dallasfrom $54

Flights to Seattlefrom $58

Cheap flights from Ontario to Illinois from $61

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 1/16. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.

Big names and deals

Big names and deals

Filter for what you want

Filter for what you want

Trusted and free

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Find the cheapest flights from Ontario to Illinois

Cheap round-trip flights

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Cheap last minute flights

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Frontier flights from Ontario to Illinois

Our best Frontier deals on Ontario to Illinois flight tickets

Delta flights from Ontario to Illinois

Our best Delta deals on Ontario to Illinois flight tickets

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Use the filters below to find and compare flights from Ontario to Illinois that are best for you.

See travel insights to Illinois from

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

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?

Our most recent data shows that the best time of day to fly to Illinois is in the afternoon. Flights from Ontario to Illinois during this time can be as low as $276. Flights in the evening are often more expensive with an average ticket price of $584.

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 to Illinois?

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?

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

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

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

What airlines fly to Illinois?

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

The number of flights available between Ontario and Illinois is 2 per day as of November 2025. The most frequent departure time is 7:00AM, with 100% of daily flights leaving at noon.

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

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

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

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

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

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

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

What is the most popular plane model 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?

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

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

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

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

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