CHI - ONT

$101 Find Cheap Flights from Chicago to Ontario

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Chicago to Ontario departing on 8/18. 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, 0 bags

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

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Chicago to Ontario, 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 Chicago to Ontario, as well as popular online travel agencies
Travelers love KAYAK
41,299,237 searches in the past 7 days on KAYAK

Save 24% or moreCompare multiple travel sites with one search.

Track pricesNot ready to book? Create a price alert for when prices drop.

Bundle and saveSave money when you bundle your flight + hotel.

Filter your dealsChoose cabin class, free Wi-Fi and more.

Everything you should know

Cheapest round-trip
$185
Typical prices: $485-$244
Frontier
Tue 5/26Fri 5/29
ORD - ONT • 1 stop
Cheapest non-stop
$298
Typical prices: $467-$317
United Airlines
Wed 5/27Wed 10/14
ORD - ONT • Non-stop
Advice from real travelers
AI-powered summary based on content written by travel experts. AI can make mistakes.
United's Economy Plus offers extra legroom benefits.
ONT provides budget-friendly public transport options.
Expert advice
Expert advice
Expert advice
Expert advice
Top airlines
Cheapest • from $185 (round-trip)
Best reviews • 7.9 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
Nonstop flights
You can fly direct with Southwest and United Airlines. Average duration is 4h 14m
Direct flights
Direct flights
+1
+1
Direct flights
Direct flights
+1
Top routes
Cheapest • 8% average savings
Most popular
Insights
Insights
Insights
Insights
Top layover airports
Cheapest • Avg $148 (round-trip)
Shortest trip • 6h 35m (one-way)
Insights
Insights
Insights
Insights
When to book
in advance
Our data shows that travelers who book at least 4 weeks in advance save around 46% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
Cheapest • 34% price drop
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
Start a new search
KAYAK searches 100s of sites at once to find you the best travel deals.
We hope you love your trip to Ontario!
Flight Deals
Booking Insights
Expert advice
Flight Deals

Cheap Flights from Chicago to Ontario (CHI-ONT)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Chicago to Ontario 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 Chicago to Ontario

Tue, May 26 - Fri, May 29
Frontier Logo
9:37 pm - 11:49 pm
ORD
-
ONT
28h 12m
1 stop
Frontier Logo
8:06 pm - 11:01 pm
ONT
-
ORD
24h 55m
1 stop
$185Frontier
Tue, Jun 9 - Tue, Jun 16
Frontier Logo
7:20 am - 3:08 pm
ORD
-
ONT
9h 48m
1 stop
Frontier Logo
3:34 pm - 5:07 am
ONT
-
ORD
11h 33m
1 stop
$198Frontier
Sun, Aug 2 - Tue, Aug 18
Frontier Logo
7:15 am - 7:53 pm
ORD
-
ONT
14h 38m
1 stop
Frontier Logo
6:00 am - 8:53 pm
ONT
-
ORD
12h 53m
1 stop
$202Frontier
Wed, Aug 12 - Tue, Aug 18
Frontier Logo
7:15 am - 3:07 pm
ORD
-
ONT
9h 52m
1 stop
Frontier Logo
10:50 am - 8:53 pm
ONT
-
ORD
8h 03m
1 stop
$210Frontier
Wed, May 27 - Wed, Oct 14
American Airlines Logo
4:45 pm - 10:36 pm
ORD
-
ONT
7h 51m
1 stop
American Airlines Logo
8:00 pm - 5:46 am
ONT
-
ORD
7h 46m
1 stop
$219American Airlines
Wed, Jul 8 - Tue, Jul 14
Frontier Logo
9:57 pm - 10:03 am
ORD
-
ONT
14h 06m
1 stop
Frontier Logo
1:28 pm - 5:28 am
ONT
-
ORD
14h 00m
1 stop
$220Frontier
Wed, May 27 - Wed, Jun 3
Delta Logo
9:23 am - 4:17 pm
MDW
-
ONT
8h 54m
2 stops
Delta Logo
6:00 am - 6:33 pm
ONT
-
MDW
10h 33m
2 stops
$247Delta
Wed, May 27 - Sat, May 30
Southwest Logo
6:10 am - 11:55 am
MDW
-
ONT
7h 45m
1 stop
Southwest Logo
11:55 pm - 5:40 am
ONT
-
MDW
3h 45mnonstop
$253Southwest
Wed, Jun 24 - Wed, Jul 1
Southwest Logo
5:30 am - 9:35 am
MDW
-
ONT
6h 05m
1 stop
Southwest Logo
4:35 pm - 12:05 am
ONT
-
MDW
5h 30m
1 stop
$259Southwest
Wed, May 27 - Sat, May 30
Delta Logo
1:22 pm - 11:34 pm
MDW
-
ONT
12h 12m
2 stops
Delta Logo
7:05 am - 4:12 pm
ONT
-
MDW
7h 07m
1 stop
$277Delta
Booking Insights

KAYAK's insights & trends for Chicago to Ontario flights

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

How much is a round-trip flight from Chicago to Ontario?

This analysis is based on the cheapest round-trip price found on KAYAK in the last 12 months by searching for a flight from Chicago to Ontario departing in May.

What is the cheapest Chicago to Ontario flight route?

Data is based on round-trip flight searches on KAYAK over the past month.

The absolute cheapest return flight from Chicago to Ontario costs $263 on the route between Chicago O'Hare Intl Airport (ORD) and Ontario (ONT). However, over the past month, flights between Chicago Midway Airport (MDW) and Ontario (ONT) were, on average, 8% cheaper than other Chicago-Ontario routes. The most popular route is between Chicago O'Hare Intl Airport (ORD) and Ontario (ONT).

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

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

For Chicago to Ontario, Wednesday is the cheapest day to fly on average and Sunday is the most expensive. Flying from Ontario back to Chicago, the best deals are generally found on Wednesday, with Sunday being the most expensive.

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

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Chicago to Ontario, 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 Chicago to Ontario is April, where tickets cost $99 (return) on average. On the other hand, the most expensive months are November and January, where the average cost of round-trip tickets is $188 and $182 respectively.

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

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 $333 on average.

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

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Chicago to Ontario, 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 Chicago to Ontario, you should book around 4 weeks before departure, which saves you about 46% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 26 weeks before departure.

Expert advice

Expert advice for your flight from Chicago to Ontario

 
AI-powered summary based on content written by travel experts. AI can make mistakes.
KAYAK teamed up with top travel experts to share the best tips for your journey.
Our travel experts
Blane Bachelor

Blane Bachelor

Expert on Southwest

Blane Bachelor is a journalist and editor specializing in travel and aviation who writes regularly for top global outlets. Born and raised in Florida, Blane has worked and lived in four countries, including the Netherlands, where she’s currently based with her family. Her favorite way to get to know a new destination is by running or riding a bike around town – or hearing a spooky ghost story about local history. She will always choose the window seat.

Stefanie Waldek

Stefanie Waldek

Expert on United Airlines, ORD and MDW

Stefanie Waldek is a freelance space, travel, and design writer based in Saratoga Springs, NY. Her words have appeared in Space.com, Travel + Leisure, Condé Nast Traveler, Architectural Digest, and House Beautiful, among other publications. An expert in aviation and expedition cruising, Stefanie is frequently up in the air or on the sea, likely en route to Antarctica or the Arctic.

Jennifer Simonson

Jennifer Simonson

Expert on ONT

Jennifer Simonson is driven by her lifelong commitment to exploring the globe. Her insatiable curiosity had led her to immerse herself into diverse locations like Oklahoma City and Pismo. Her hotel recommendations are the result of the myriad hotels she's stayed at across her travels. Along her journey, she cherishes engaging conversations with locals, indulging in the finest ice cream, trying her hand at surfing, and embarking on nature-filled hikes.

Good to know

Low seasonJanuary
Cheapest flight$101
Best time to beat the crowds but there is an average 30% increase in price.
Most popular time to fly and prices are also 7% lower on average.
Flight from Chicago O'Hare Airport to Ontario

When to book flights from Chicago to Ontario

Are your dates flexible? Find out the best times to travel from Chicago to Ontario based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking flights from Chicago to Ontario

  • What are the most common layover airports for flights from Chicago to Ontario?

    Some of the most typical layover airports for various airlines traveling from Chicago to Ontario are Phoenix Sky Harbor International Airport (PHX), Dallas/Fort Worth International Airport (DFW), and Denver International Airport (DEN). If you are flying with American Airlines, your layover airports will be PHX or DFW. DEN, on the other hand, serves as a layover airport for Frontier aircraft.

  • Which airline(s) should I book if I am to travel with my pet(s) from Chicago to Ontario?

    Although most airlines flying from Chicago to Ontario allow pets, booking with Alaska Airlines has a number of advantages for pet owners. When compared to other airlines on this route, Alaska features some of the lowest pet fees. Furthermore, pets are permitted to travel in-cabin as long as their combined weight with that of the carrier does not exceed 20 lbs.

  • Can I get an eco-friendly flight from Chicago to Ontario?

    Yes. Several airlines operating from Chicago to Ontario - including Delta, American Airlines, and Spirit Airlines - provide environmentally friendly flights between Chicago and Ontario. Among them, American Airlines leads the list as one of the most environmentally friendly airlines because of its carbon reduction projects, which aim to equip all of its planes with fuel-efficient engines.

  • Which airline(s) among those flying from Chicago to Ontario have an option to upgrade from economy to first class?

    Delta Airlines, American Airlines, and Spirit Airlines are among the airlines where you can upgrade to first class by adding a nominal fee to your ticket. By taking advantage of this opportunity, you can fly first class at a lower rate than if you booked first class directly.

  • What is the cheapest flight from Chicago to Ontario?

    In the last 3 days, the lowest price for a flight from Chicago to Ontario was $101 for a one-way ticket and $185 for a round-trip.

  • Do I need a passport to fly between Chicago and Ontario?

    Even though you are not required to have a passport, keep in mind that an official ID is needed to board the airplane.

  • Which airports will I be using when flying from Chicago to Ontario?

    On your way to Ontario, you’ll fly out from one of these Chicago airports: Chicago Midway or Chicago O'Hare Intl. You’ll be landing at Ontario.

  • Which airlines offer Wi-Fi service onboard planes from Chicago to Ontario?

    American Airlines, JetBlue, and Alaska Airlines offer inflight Wi-Fi service on the Chicago to Ontario flight route.

  • Which aircraft models fly most regularly from Chicago to Ontario?

    The Boeing 737 MAX 8 is the aircraft model that flies most regularly on the Chicago to Ontario flight route.

  • Which airline alliances offer flights from Chicago to Ontario?

    SkyTeam, oneworld, and Star Alliance are the airline alliances operating flights between Chicago and Ontario, with SkyTeam being the most commonly used for this route.

  • On which days can I fly direct from Chicago to Ontario?

    There are nonstop flights from Chicago to Ontario on a daily basis.

  • Which is the best airline for flights from Chicago to Ontario, Southwest or United Airlines?

    The two airlines most popular with KAYAK users for flights from Chicago to Ontario are Southwest and United Airlines. With an average price for the route of $532 and an overall rating of 7.9, Southwest is the most popular choice. United Airlines is also a great choice for the route, with an average price of $533 and an overall rating of 7.4.

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

    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 Chicago to Ontario.

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

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Ontario from Chicago 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 Chicago to Ontario?

    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 to Ontario with an airline and back to Chicago with another airline.

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

    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 to Ontario from Chicago up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

KAYAK’s top tips for finding a cheap flight from Chicago to Ontario

  • Looking for a cheap flight? 25% of our users found flights on this route for $168 or less one-way and $406 or less round-trip.
  • Chicago O'Hare International Airport (ORD) is the primary departure airport for flights from Chicago to Ontario. However, just a few flights leave from Chicago Midway International Airport (MDW). You have a better chance of finding a cheaper flight fare if you choose a less popular route with MDW as the departing airport. Ontario International Airport (ONT) is the only airport serving all flights from Chicago to Ontario.
  • When traveling from Downtown Chicago to ORD to catch a trip to Ontario, CTA Blue Line buses are the most cost-effective and dependable mode of transportation. However, if you are in a hurry, consider taking cabs - which are the quickest mode of transportation.
  • Booking with American Airlines or United Airlines, both of which use ORD as their hub, gives you the assurance of getting a flight that fits your schedule. This is due to the fact that both airlines operate the most daily flights from Chicago ORD to Ontario.
  • Consider flying Delta or American Airlines from Chicago to Ontario with your child(ren). Because of the big seats and extra legroom in all American Airlines cabins, you and your children will travel in luxury. Furthermore, both Delta and American Airlines give priority boarding to parents traveling with their children.
  • When you book a trip from Chicago to Ontario, you will have the option of connecting to a variety of different cities covered by ONT. Upland, Montclair, and Chino - just a few of the cities with easy access from Ontario International Airport.

Prefer to fly direct from Chicago to Ontario?

 
Direct data is based off flight results for the next 60 days. Find direct flights from all airlines flying direct from Chicago to Ontario.
Find which airlines fly direct from Chicago to Ontario Airport, which days they fly and book direct flights.

Direct departures

Chicago to Ontario

Monday

Southwest,United Airlines

Southwest,United Airlines

Tuesday

Southwest,United Airlines

Southwest,United Airlines

Wednesday

Southwest,United Airlines

Southwest,United Airlines

Thursday

Southwest,United Airlines

Southwest,United Airlines

Friday

Southwest,United Airlines

Southwest,United Airlines

Saturday

Southwest,United Airlines

Southwest,United Airlines

Sunday

Southwest,United Airlines

Southwest,United Airlines

See more direct flights

Direct returns

Ontario to Chicago

Monday

Southwest,United Airlines

Southwest,United Airlines

Tuesday

Southwest,United Airlines

Southwest,United Airlines

Wednesday

Southwest,United Airlines

Southwest,United Airlines

Thursday

Southwest,United Airlines

Southwest,United Airlines

Friday

Southwest,United Airlines

Southwest,United Airlines

Saturday

Southwest,United Airlines

Southwest,United Airlines

Sunday

Southwest,United Airlines

Southwest,United Airlines

See more direct flights

Reviews of the top 3 airlines serving from Chicago to Ontario

 
See real verified KAYAK customer reviews for airlines flying from Chicago to Ontario. 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 Chicago to Ontario? 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.
7.9
SouthwestOverall score based on 4303 reviews
7.0Food
8.0Comfort
7.5Entertainment
8.6Crew
8.1Boarding
Airline reviews

Not having a five hour delay with little notice! The crew was very kind, though, and just as tired as we passengers were. The flight didn't depart until nearly 1 am...and no reason was ever given.

2.0 MediocreAnonymous, May 2026
SEA - SMF
Read more Southwest reviews

Not having a five hour delay with little notice! The crew was very kind, though, and just as tired as we passengers were. The flight didn't depart until nearly 1 am...and no reason was ever given.

This leg was much better, but we did have to have a 3 hour lay o er after coming from a very exhausting hiccup with our flight from BNA to Den

The Air hostess were very rude on my flight from Houston to Austin . Their regular communication itself felt a they are shouting at people.

I flew twice this week on Southwest, was delayed over 2 hours both ways. From Pittsburgh to Chicago it was due to weather but the gate agents, pilot etc were great at updating everyone. Today from Midway to Pittsburgh the plane had come from an international location, kept getting delayed, no information was given until we were delayed for the third time. It was ridiculous, whoever scheduled that plane to fly to Pittsburgh after didn’t consider a lot of things.

Boarding was easy. The seats are small and fairly uncomfortable

The problem with the seat assignments is that there were a lot of rows in the front that were empty but my row at the back was full. Just not so pleasant.

No food or entertainment, just a quick 40 minute flight. A little bumpy due to Santa Ana winds but pilot has no control over that. Good flight and landing!

Good but I prefer choose your own seat. With the new assigned seats they should board from the back I see no advantage to this new boarding. Just like every other airline

Mediocre. Boarding is now unpleasant. The employees, once friendly and nice, are now regularly speaking sternly to passengers, badgering them to do things right so they can take off on time and gate check bags because they don't have enough overhead bin space. The pretzel snack was crushed flat and broken into even smaller pieces, which happens frequently lately. Drink service was suspended before they reached my row.

The charges were ridiculous for an hour flight and the turbulence was very scary.

A long delay. Don't travel late in the day.

Super friendly with lots of drink options an entertainment. Friendly crew.

The crew was great. Very friendly and responsive. The plane was old, small and tight. We ran out of overhead space and I had to check. Middle seat was particularly tight.

Several missed and almost missed connections. It felt like everything was being patched together last minute without enough resources and it ended up being an extremely stressful experience that basically ruined our weekend on the west coast. What a waste.

Crew was friendly. Seats are too narrow, particularly when a big person is in the adjacent seat, but I understand this is due to smaller planes usually flight into Lincoln. I have experienced several flight delays going out and coming into Lincoln airport, I say maybe 50% or higher of the flights I've taken out of this airport have been delayed.

Great flight. Boarded efficiently. Arrived early at CLT. There was no in flight entertainment on this aircraft. Great crew.

The seat was comfortable. There was a lot of turbulence. If it weren't for that,it would have been okay.

Poor communication, flight was delayed for preventable reasons. I missed my connection.

No meal service to the back of the plane as it started late or was too slow to get it out before it was time to land.

Terrible, if possible won't be flying again anytime soon!

Frontier scheduled a 40 minute connection in DEN. What they failed to mention was that they “close the doors” 20 mins prior to departure, which means you only have 20 mins. Not enough time. Possibly against DOT regulations. Filing complaint.

Flight was scheduled at 9:40pm. Got delayed to 10 am, the next day. crazy

The bag check, flight check-in, and onboard experience convinced my wife and me that we will actively go out of our way to avoid flying Frontier Airlines in the future. At bag check, we were informed that check-in could only be completed via the Frontier mobile app. Unfortunately, the app was extremely frustrating—sending us through repetitive, confusing loops that repeatedly forced us to decline add-on services with nearly every click. While most airline apps upsell, this one felt intentionally exhausting. As the process dragged on, we became genuinely concerned that my phone battery would die before check-in could be completed. We approached the bag check staff—who were standing together talking—and explained both our frustration and our predicament. They laughed. Later, my wife described the interaction as “gaslighting,” which felt accurate. We were then informed it would cost $25 per person simply to have our boarding passes printed. From that point forward, the tone of the experience was consistently hostile. The bag check employees were condescending and combative, behaving more like bullies than customer service staff. Unfortunately, that same attitude continued onboard. One flight attendant argued with me when I attempted to stow my backpack in the overhead bin. I explained that we had each paid $75 to check our bags specifically so we would not need to use carry-on space and could have adequate legroom. She demanded to see my ticket, pointed out that it said “no carry-on”—which I acknowledged—and I reiterated that this was precisely why we paid to check our bags. Her response was, “I don’t make the rules.” She then walked away, but not before asking if I “truly wanted to fly back to Chicago today?”—an unnecessary and unmistakable threat. It is also worth noting that despite booking our tickets together in the same transaction, we were not seated together. Upon our return to Chicago—where we could once again sit together—we compared onboard experiences. We both remarked on how unhappy the flight attendants appeared and how each of us was separately asked whether we would like to purchase a beverage. We declined. At no point was water mentioned as an option, leaving us with the clear impression that even water came at a cost—or that complimentary water, if available at all, was deliberately left unmentioned. Overall, the experience was shocking and deeply disappointing, but it was also a profound learning experience—one we will not forget and will not repeat. -Steve

Plane was hot and miserable and the crew was rude!

12 hour delay required getting on and off plane 3 times - would have at least liked to have been offered a snack or drink

They didn’t offer a water, even after I asked

They switched our terminal 3 times and we were delayed for four plus hours!!!

It was an early flight and most people napped/slept and the crew let us which was nice.

Flight was canceled. Most upsetting was message from Kayak, stating that the flight was canceled and click with Kayak for details regarding rebook, refund details. THERE'S NO INFORMATION PROVIDED BY KAYAK EXCEPT THAT FLIGHT IS CANCELED. AND NOW THIS SURVEY TO FIND OUT HOW WAS THE FLIGHT !!!!!!!

Our flight was canceled. I will never use Kayak nor Frontier for travel again. The entire experience was a headache.

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

Information on your arrival and departure airports