$78 Find Cheap Flights from Ontario to Illinois

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Ontario to Illinois departing on 8/27. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy

KAYAK searches hundreds of travel sites at once for deals on flights to Illinois

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Ontario to Illinois, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Ontario to Illinois, as well as popular online travel agencies
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Cheap Flights from Ontario to Illinois

Cheapest round-trip prices found by our users on KAYAK in the last 72 hours
Chicago
Chicagononstop$173
Moline
Moline1 stop$289
Peoria
Peoria1 stop$354
Bloomington
Bloomington1 stop$379
St. Louis
St. Louis1 stop$195
Chicago
Chicagononstop$173
Moline
Moline1 stop$289
Peoria
Peoria1 stop$354
Bloomington
Bloomington1 stop$379
St. Louis
St. Louis1 stop$195

Book Cheap Ontario to Illinois Plane Tickets

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Ontario to Illinois that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Ontario to Illinois

Wed, Sep 17 - Wed, Sep 24
United Airlines Logo
7:00 am - 1:03 pmONT-ORD
4h 03mnonstop
United Airlines Logo
7:59 pm - 10:30 pmORD-ONT
4h 31mnonstop
$173United Airlines
Find Deal
Mon, Sep 1 - Wed, Sep 10
United Airlines Logo
7:00 am - 1:03 pmONT-ORD
4h 03mnonstop
United Airlines Logo
7:59 pm - 10:30 pmORD-ONT
4h 31mnonstop
$190United Airlines
Find Deal
Wed, Sep 3 - Tue, Sep 16
American Airlines Logo
12:45 pm - 11:59 pmONT-ORD
9h 14m1 stop
American Airlines Logo
6:00 am - 11:57 amORD-ONT
7h 57m1 stop
$193American Airlines
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Tue, Sep 2 - Tue, Sep 9
American Airlines Logo
4:54 pm - 12:16 amONT-STL
5h 22m1 stop
American Airlines Logo
8:50 am - 1:54 pmSTL-ONT
7h 04m1 stop
$195American Airlines
Find Deal
Tue, Sep 9 - Thu, Sep 11
Southwest Logo
9:00 pm - 5:10 amONT-MDW
6h 10m1 stop
Southwest Logo
8:20 pm - 10:30 pmMDW-ONT
4h 10mnonstop
$200Southwest
Find Deal
Wed, Sep 10 - Tue, Sep 16
Southwest Logo
3:35 pm - 10:35 pmONT-STL
5h 00m1 stop
Southwest Logo
6:20 am - 9:35 amSTL-ONT
5h 15m1 stop
$204Southwest
Find Deal
Fri, Aug 22 - Tue, Aug 26
Frontier Logo
12:59 am - 9:11 amONT-STL
6h 12m1 stop
Frontier Logo
7:54 pm - 11:50 pmSTL-ONT
5h 56m1 stop
$210Frontier
Find Deal
Mon, Aug 18 - Tue, Aug 26
Frontier Logo
12:59 am - 9:11 amONT-STL
6h 12m1 stop
Frontier Logo
7:54 pm - 11:50 pmSTL-ONT
5h 56m1 stop
$216Frontier
Find Deal
Wed, Sep 3 - Tue, Sep 16
Delta Logo
11:45 am - 9:26 pmONT-MDW
7h 41m1 stop
Delta Logo
12:43 pm - 7:15 pmMDW-ONT
8h 32m1 stop
$257Delta
Find Deal
Wed, Sep 3 - Sat, Sep 13
Delta Logo
11:45 am - 9:26 pmONT-MDW
7h 41m1 stop
Delta Logo
9:35 am - 7:15 pmMDW-ONT
11h 40m2 stops
$262Delta
Find Deal
Booking Insights

KAYAK's insights & trends for Ontario to Illinois flights

Get data-powered insights and trends into flights from Ontario to Illinois to help you find the cheapest flights, the best time to fly and much more.

What is the cheapest Ontario to Illinois flight route?

The cheapest price for flight routes found by users searching on KAYAK in the last 2 weeks for round-trip flights from Ontario to Illinois.

The cheapest ticket to Illinois from Ontario found in the last 72 hours was to Chicago, at $258 round-trip. The most popular route is from Ontario (ONT) to Chicago O'Hare Intl Airport (ORD), and the cheapest round-trip airline ticket found on this route in the last 72 hours was $295.

Can I save money by flying with a layover from Ontario to Illinois?

The average round-trip price for all non-stop flights, flights with one layover, and flights with two layovers for the route found by users searching on KAYAK in the last 2 weeks.

Yes, flying with a layover may cost you more time, but you can also save money on the route, with a 1 stop layover the cheapest option at $635 on average.

What is the cheapest month to fly from Ontario to Illinois?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Ontario to Illinois, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from Ontario to Illinois is November, when tickets cost $227 (return) on average. On the other hand, the most expensive months are March and May, when the average cost of round-trip tickets is $458 and $387 respectively.

What’s the cheapest day of the week to fly from Ontario to Illinois?

The average price of all round-trip flights from Ontario to Illinois clicked on KAYAK for each day over the last 12 months.

If your flying dates are flexible, you should consider flying to Illinois on a Thursday, as we generally find the cheapest rates on that day for this route. On the other hand, Sunday is the most expensive day to fly from Ontario to Illinois. For your return ticket, we recommend flying on a Wednesday and avoiding Mondays for the best deals.

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

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Ontario to Illinois, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from Ontario to Illinois, you should book around 3 weeks before departure, which saves you about 50% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 3 weeks before departure.


Good to know

Low seasonJanuary
Cheapest flight$78
Best time to beat the crowds with an average 16% drop in price.
Most popular time to fly and prices are also 3% lower on average.
Flight from Ontario to Chicago O'Hare Airport

FAQs - booking Illinois flights

  • How does KAYAK find such low prices on flights from Ontario to Illinois?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Ontario to Illinois.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Ontario to Illinois?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight from Ontario to Illinois is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Ontario to Illinois?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly from Ontario to Illinois with an airline and back with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Ontario to Illinois?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying from Ontario to Illinois up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

  • What is the cheapest time of day to fly to Illinois?

    The cheapest time of day to fly to Illinois is generally in the evening, when round-trip flights cost $276 on average. Morning departures are around 62% more expensive than evening flights, on average. The most expensive time of day to fly to Illinois is generally in the afternoon, which is peak travel time and where the average cost of a ticket is $531.

Top tips for finding cheap flights to Illinois

  • Looking for a cheap flight? 25% of our users found tickets from Ontario to the following destinations at these prices or less: Chicago $163 one-way - $409 round-trip

Reviews of the top 5 airlines serving from Ontario to Illinois

 
See real verified KAYAK customer reviews for airlines flying from Ontario to Illinois. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Ontario to Illinois? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
8.0
SouthwestOverall score based on 4246 reviews
8.0Comfort
7.0Food
8.6Crew
8.1Boarding
7.5Entertainment
Airline reviews

Worst experience I had on Southwest. Still better than most, but the seating was barely tolerable.

4.0 OkayBobby, Jul 2025BNA - MDW
Read more Southwest reviews

Worst experience I had on Southwest. Still better than most, but the seating was barely tolerable.

It was okay. The plane was delayed from earlier in the day, but they kept updating the departure time, sometimes later, sometimes earlier. That was stressful. Once we finally got on and took off, it was fine. I was supposed to have a connection in Chicago to Los Angeles, and the time for so late I was rebooked to arrive in LA 3 hours late. The departure time to Chicago later became early enough to have taken my original connection and arrive earlier but that wasn't an option.

Delayed flight. Nicest crew member was a SW pilot flying seated next to me who kindly move to seat the final passenger. Flight extra delayed. My cup of refreshment of ginger ale was so packed with ice it was literally 2 sips.

No trays in our seats, we sat in first row, purchased a business class fare. Had to hold our drinks and snack in our hands. No plugs for our cell phones. Had to pay for it a drink cocktail each. Seats so uncomfortable.

Flight wasn’t even full, but too many carry-ons caused us to run out of bin space. New bag fee has folks who would usually check their bags carrying on. Watching Southwest morph into Spirit/Frontier is so sad to watch

Everything was on time. I was disappointed by the front section female, African American flight attendant. I did not see her name tag or would have identified by name not race. As passengers moved to the bathroom early in flight, she would say with a disdainful tone “I have to say the seat belt light is on” then go back to her book. Better trained flight attendants say something like be careful the seat belt light is on.

Southwest is Southwest. No frills. If you're luck enough to get a happy crew (we did), then it makes for a nicer flight.

It was a perfect flight in all aspects! Both legs!

Great flight, 47 passengers on a 180 seat plane. Stewardess was pleasant and cheerful.

I liked the crew member who gave flight instructions on "in case of a problem:. The seats are so small that only a young teenager could sit in middle seat.

My husband upgraded our seats and I don't know if it was due to the type of planet was or if they didn't upgrade our seats. We were supposed to be in I believe comfort seats and they were just as tight as any other seat- no leg room and we are very tall people but at least it wasn't extremely cold. My husband did put in a complaint about our seating because he paid extra and if we would have known that the space and the tightness would have been the same, we just would have gotten the emergency row emergency row seats that we normally get. We love Delta but both our flights coming home we're not good. Oh I forgot to mention that on our flight to Hawaii our luggage wheels got broke and we had to purse new luggage on vacation then we never had this problem so we didn't know protocol and reported it after we got home only for them to tell is we only had 24hrs to report the damage. Not sure what was going on with Delta this vacation trip.

Crew was excellent. Comfort seats not as nice as other kinds of planes.

It was a great flight and the stewards and stewardess were all kind and accommodating!! The seats were comfortable and entertainment screen excellent!

There are 4 flights in consecutive gates with about the same departure time. Two flights were boarding at the same time. One was delayed or boarding would be happening at the same time. I am not sure what Delta and LAX need to do to have a better layout at the end of Terminal 2

There was a security issue at the airport and we were unable to land. We circled endlessly and then landed at another airfield for fuel. We then circled the airport again, almost landed but didn’t fully touch down before circling again. I am thankful to the crew for keeping us safe- the issue was the airline and staff at the airport getting us seats on our connecting flights. That part was hours of searching for someone and getting in double my steps.

Most aspects were good however if they assign boarding zones they ought to enforce them or why bother? My luggage from SAN-JFK-MAD was lost in NY so I without my main bag for two days upon arrival in Spain. They were helpful in tracking it and eventually delivered it to my hotel. The flub was because of a delay upon arrival in NYC. I had booked 2 1/2 hours between flights but we had to hold on the taxiway for an hour after landing while waiting for a clear gate which likely caused the baggage error.

Excellent flight, the planes were newer, they did a nice job with boarding, great service overall.

It would be nice if was given wires ear buds. Overall was a good experience was able to sleep on the plane

737-800 in first class was pretty dumpy. Seat had an uncomfortable angle, storage under the seat was blocked so even my very modest backpack didn't fit, power outlet was flaky. Weird tiny seat pockets that couldn't hold a gallon ziploc bag, emesis bag missing, etc. etc. No in-flight service due to turbulence. Crew was excellent, boarding was smooth despite a full flight.

Delta flight was on time, seats were comfortable, and crew was nice.

Weather delay in Chicago?. No sense of urgency to make connection in Chicago for our connecting flight that wasn't delayed. Connection was missed.

Overall it was good. I missed my connection but I was put on another flight.

Overall a very poor experience - booked premium economy tickets but due to last minute flight delays , all my itinery went for a toss and had to fly economy class with no access to lounge or any compensation by united airlines to make up for the flight delays . i had expected better experience than that from united.

It was fine, definitely older planes with no charging or anything. There’s no entertainment set up on board, but it is nice that they allow you to access the in flight entertainment from your phone without having to pay for the Wi-Fi and they do offer free texting.

I liked that the flight was nonstop from ORD to CIU for $200 round trip.

The schedule to Moline changed 5 times. The gate changed 6 times. That is a pathetic way to run an airline. No wonder that no one in our company flies on United Express to or from Moline. Changes happen most of the time. I learned my lesson on this trip…never again!

While the staff was pleasant and helpful, the following observations are for your awareness. There was some delay on the tarmac on take off and landing. The paid lunch/food offerings were limited. Entertainment was only available on WiFi at a cost.

The first flight was better in terms of the aircraft.

Smooth flight. Boarding was chaotic. Could not hear the gate agent over the intercom. People were lined up in the wrong lines. Groups one and two were told to board through line one and group 3 through line 2. All very confusing. Once in the air, the flight was smooth. There was no entertainment option on this aircraft, even though it was a larger aircraft.

Overall poor for me I paid extra for seats with leg room and my regional flights exit row seats have less leg room then the others that's money that could have been saved and on my final flight home the flights air was not operating it was unbearably hot in the cabin I will be contacting United and filing a DOT complaint

Dreadful experience. Our flight was delayed more than 8 hours due to a maintenance issue and the assistance from rebooking was poor. I was travelling with a bad knee and needed assistance waited in one place more than 3 hours before someone came with a wheelchair. The woman next to me was a 91 year old great grandmother who had waited more than 4 hours. There were moments of support from the staff but it appeared as they were going against the direction of management. It was apathy, lack of ownership and dismissive responses with small moments of kindness and understanding typically from grey haired, female, veteran staff..

Couldn’t get the door on the plane to close leading to a nearly 2 hour delay. But, hey at least they didn’t cancel the flight.

The flight was fine and the crew awesome. The problem is ORD and AA. Computers went down, ORD fell apart and a 40 min flight turned into a 3 hour trip. Guess the answer is to not try and fly to ORD after noon. But, as I said, crew was awesome and did everything they could to lesson the flight time.

The flight was fine but the 8 hour delay in Chicago was awful - 5 gate changes and repeated delays without an explanation. No vouchers. Nothing.

The chair cushions may need an upgrade. I have been noticing they are so worn out, thin so you’d sit in a dip 😄. Other than that, all was an enjoyable trip. Thanks AA!

Most miserable flight ever. We waited almost 2 hours on the runway because the flight was oversold. American offered $1200 credit. Then there was some nonsense about weight distribution. Ridiculous. No food for 8 plus hours on the flight. I will be writing a letter.

The flight was 2 hour delayed, otherwise everything was excellent. The delay was due to the hourly limit requirement so given that as a reason, I'm happy with the flight!

Not sure the logic of the boarding in Groups. I was loaded first on the aisle. Then the guy in the middle. Then the guy by the window. Constantly holding up the other people boarding behind them with us blocking the aisle and this happened in most of the other rows

To start, I’d like to say that every American Airline personnel I interacted with on the ground, especially flight crew, was very friendly and did their best to help me out. Despite this, however, my experience with the airline was an entire mess. The 7:19 PM flight was heavily delayed due to weather, and pushed to 10:30 AM the next morning. Because of this, I had to spend the night inside of the airport. At some point later in the night, I got an email saying that the flight had been canceled. I called the support number, and the representative on the other line told me that the flight was still on and that I didn’t need to rebook. The next morning, no one came to the gate to open the door for the crew until almost 11 AM. By this time the flight crew had been waiting for over an hour, and they had called management to get someone to open the door for them multiple times. Around 11:30, the gate screen had changed to a different flight. I ended up buying a last minute ticket with Southwest airline just to get to Chicago, because the next flight with American wasn’t until 7:19 pm that day. Now, earlier that morning my suitcase had been sent ahead of me to ORD. I went to baggage claim to ask them if I could have my suitcase forwarded to where I was staying. The representative at SDF baggage claim said they could and put the claim in for me. As I was going back through TSA, I got an email that the airline had found my suitcase, but the next step was to send it BACK to SDF. I called the airline support number again, and I made it clear that my suitcase needed to stay in Chicago and to not come back to SDF. The representative told me that they would hold my suitcase at ORD and that it wasn’t going to be forwarded anywhere. Once I got there, I found that they had loaded my suitcase onto a plane to send it back to SDF. Thankfully, I had gotten to the baggage claim counter in time for them to put in a request to bring my suitcase back up. My refund with the airline is processing already, but because of this entire experience and miscommunication at every turn of the way, I will not book with American Airlines in the future.

The plane was late and then sat on the runway for almost 45 minutes before taking off.

Severe turbulence. Captain never came on to reassure passengers after things settled down.

We were delayed three times ,and that destroyed my plans, and reservations

Cancelled flight after I arrived at airport after 75 min drive and parking. Next flight was 4 days in the future. Had to scramble and buy a much more expensive flight on another carrier.

I liked the turn-style feature at gate 209B at LAX. Very efficient process. The gate staff also made several, clearly directed announcements so I felt very informed.

The crew was delayed because they came on another flight that was delayed due to weather 10pm flight left at 1.30 am The airline made no effort to align alternate crew

The seats were awful, hard plastic covered in sheet vinyl. The airline tries to scam you into paying extra to get seat together when the flight wasn’t full. They were going to separate a family with young children but my wife who had a row to herself gave up her seat so the young mom could be with her young boys. I’m never giving this airline my money again.

It was a short flight so no food or entertainment….

Frontier had yet another flight cancellation. Have never made a complete round trip with this airline without at least one leg getting cancelled. Miserable flights - dirty, uncomfortable planes that apparently always have issues since I've had multiple delays and cancellations with them.

Flight was delayed 3 times, would have been nice to have received text message instead of email notifications. Frontier app wasn’t even updated accordingly, no gate number disclosed. No agent at front desk of gate to inform of delay. Very confused and left if the dark

The flight itself was ok and the pilot was very communicative. However, our flight was delayed for almost 3 hours, the gate was changed 3 times and there was no communication as we were waiting. The flight staff was overall a little crabby...I understand as they probably had a long day but we all did.

Everything you need to know for your flight from Ontario to Illinois

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