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Cheap flights from Illinois to Los Angeles from $84

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 9/19. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
0 bags

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Cheap round-trip flights

United Airlines Logo
7:59 pm - 10:30 pmORD-ONT
4h 31mnonstop
United Airlines Logo
7:00 am - 1:03 pmONT-ORD
4h 03mnonstop
$173United Airlines
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Wed, Sep 17 - Tue, Sep 23
United Airlines Logo
7:59 pm - 10:30 pmORD-ONT
4h 31mnonstop
United Airlines Logo
7:02 am - 1:05 pmONT-ORD
4h 03mnonstop
$190United Airlines
Find Deal
Fri, Oct 10 - Wed, Oct 22
Southwest Logo
5:30 am - 9:40 amMDW-ONT
6h 10m1 stop
Southwest Logo
7:00 am - 4:40 pmONT-MDW
7h 40m1 stop
$192Southwest
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Tue, Nov 11 - Sat, Nov 15
American Airlines Logo
12:33 pm - 9:24 pmORD-ONT
10h 51m1 stop
American Airlines Logo
10:35 pm - 10:43 amONT-ORD
10h 08m1 stop
$193American Airlines
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Wed, Sep 17 - Tue, Sep 23
American Airlines Logo
5:18 am - 11:57 amSTL-ONT
8h 39m1 stop
American Airlines Logo
10:35 pm - 9:16 amONT-STL
8h 41m1 stop
$195American Airlines
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Tue, Sep 16 - Tue, Sep 30
Alaska Airlines Logo
6:20 am - 2:12 pmORD-ONT
9h 52m1 stop
Alaska Airlines Logo
11:39 am - 12:03 amONT-ORD
10h 24m1 stop
$203Alaska Airlines
Find Deal
Wed, Sep 3 - Wed, Sep 10
Alaska Airlines Logo
8:00 am - 2:12 pmORD-ONT
8h 12m1 stop
Alaska Airlines Logo
11:39 am - 12:03 amONT-ORD
10h 24m1 stop
$214Alaska Airlines
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Thu, Sep 11 - Tue, Sep 16
Frontier Logo
7:52 pm - 11:50 pmSTL-ONT
5h 58m1 stop
Frontier Logo
12:59 am - 9:07 amONT-STL
6h 08m1 stop
$216Frontier
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Wed, Oct 22 - Fri, Oct 24
Frontier Logo
7:54 pm - 11:50 pmSTL-ONT
5h 56m1 stop
Frontier Logo
12:59 am - 9:11 amONT-STL
6h 12m1 stop
$218Frontier
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Wed, Aug 27 - Fri, Aug 29
Southwest Logo
10:15 am - 7:15 pmSTL-ONT
11h 00m2 stops
Southwest Logo
9:10 am - 7:45 pmONT-STL
8h 35m2 stops
$276Southwest
Find Deal
Tue, Dec 9 - Sat, Dec 13

Southwest flights from Illinois to Ontario

Our best Southwest deals on Illinois to Ontario flight tickets
Southwest
Nov 11
MDW5:30 amChicago Midway
6h 10m
1 stop
ONT9:40 amOntario
Nov 15
ONT7:00 amOntario
7h 40m
1 stop
MDW4:40 pmChicago Midway
$192
Find similar
Southwest
Dec 9
STL10:15 amLambert-St Louis
11h 00m
2 stops
ONT7:15 pmOntario
Dec 13
ONT9:10 amOntario
8h 35m
2 stops
STL7:45 pmLambert-St Louis
$276
Find similar
Southwest
Aug 28
MDW8:20 pmChicago Midway
4h 10m
ONT10:30 pmOntario
Sep 1
ONT6:40 amOntario
3h 55m
MDW12:35 pmChicago Midway
$317
Find similar

Alaska Airlines flights from Illinois to Ontario

Our best Alaska Airlines deals on Illinois to Ontario flight tickets
Alaska Airlines
Sep 3
ORD6:20 amChicago O'Hare Intl
9h 52m
1 stop
ONT2:12 pmOntario
Sep 10
ONT11:39 amOntario
10h 24m
1 stop
ORD12:03 amChicago O'Hare Intl
$203
Find similar
Alaska Airlines
Sep 11
ORD8:00 amChicago O'Hare Intl
8h 12m
1 stop
ONT2:12 pmOntario
Sep 16
ONT11:39 amOntario
10h 24m
1 stop
ORD12:03 amChicago O'Hare Intl
$214
Find similar
Alaska Airlines
Sep 11
ORD6:20 amChicago O'Hare Intl
9h 52m
1 stop
ONT2:12 pmOntario
Sep 15
ONT7:47 pmOntario
9h 16m
1 stop
ORD7:03 amChicago O'Hare Intl
$226
Find similar

momondo Fare Finder

 
Customize your flight search to find flights from Illinois to Ontario that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, momondo users made 832,500 searches. Data last updated August 5, 2025.
Use the filters below to find and compare flights from Illinois to Ontario that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Wed 9/17

7:59 pm-10:30 pm

Nonstop4h 31m

Ontario

Tue 9/23

7:00 am-1:03 pm

Nonstop4h 03m

$173

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Fri 10/10

7:59 pm-10:30 pm

Nonstop4h 31m

Ontario

Wed 10/22

7:02 am-1:05 pm

Nonstop4h 03m

$190

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

Tue 11/11

5:30 am-9:40 am

1 stop6h 10m

Ontario

Sat 11/15

7:00 am-4:40 pm

1 stop7h 40m

$192

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Wed 9/17

12:33 pm-9:24 pm

1 stop10h 51m

Ontario

Tue 9/23

10:35 pm-10:43 am

1 stop10h 08m

$193

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Tue 9/16

5:18 am-11:57 am

1 stop8h 39m

Ontario

Tue 9/30

10:35 pm-9:16 am

1 stop8h 41m

$195

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Wed 9/3

6:20 am-2:12 pm

1 stop9h 52m

Ontario

Wed 9/10

11:39 am-12:03 am

1 stop10h 24m

$203

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Thu 9/11

8:00 am-2:12 pm

1 stop8h 12m

Ontario

Tue 9/16

11:39 am-12:03 am

1 stop10h 24m

$214

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Wed 10/22

7:52 pm-11:50 pm

1 stop5h 58m

Ontario

Fri 10/24

12:59 am-9:07 am

1 stop6h 08m

$216

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Wed 8/27

7:54 pm-11:50 pm

1 stop5h 56m

Ontario

Fri 8/29

12:59 am-9:11 am

1 stop6h 12m

$218

St. LouisOntario

STL - ONT

STLONT

Lambert-St Louis

Tue 12/9

10:15 am-7:15 pm

2 stops11h 00m

Ontario

Sat 12/13

9:10 am-7:45 pm

2 stops8h 35m

$276

Flights are sorted by cheapest round-trip flights first.

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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?

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 $148. If you aren’t able to travel during the month of November, then book flights to Ontario from Illinois during September instead. Flights to Ontario in September, while not as cheap as those in November, still average around $159.

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 $318. 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 afternoon when prices are $440 on average. Flights to Ontario from Illinois in the afternoon 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 $326 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 35% 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

$84

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 $84. The best round-trip flight deal from Illinois to Ontario found on momondo in the last 72 hours is $173.
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?

  • 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?

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
FrontierPriceFrom $121Free CancellationRating
5.8
3,232 reviews
Search Frontier flights
American AirlinesPriceFrom $231Free CancellationRating
7.2
10,000 reviews
Search American Airlines flights
United AirlinesPriceFrom $237Free CancellationRating
7.4
8,916 reviews
Search United Airlines flights
DeltaPriceFrom $246Free CancellationRating
8.0
7,985 reviews
Search Delta flights
SouthwestPriceFrom $246Free CancellationRating
8.0
4,246 reviews
Search Southwest 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.

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