CHI - ONT

$98 Find Cheap Flights from Chicago to Ontario - Compare and Save

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 8/11. 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

Save 21% or more on flights. Compare deals from all over the web.

Never overpay with our price tracking tools.

Filter searches by price, airline and more to find your best flights.

Everything you should know

Cheapest round-trip
$221
Typical prices: $316-$575
Frontier
Sat 9/12Tue 9/15
ORD - ONT • 1 stop
Cheapest non-stop
$239
Southwest
Wed 8/19Sat 8/29
MDW - ONT • Non-stop
Advice from real travelers
AI-powered summary based on content written by travel experts. AI can make mistakes.
United Economy Plus adds up to six inches more legroom than standard economy.
Southwest offers free snacks; United Priority Boarding helps protect carry-on space.
Expert advice
Expert advice
Expert advice
Expert advice
Top airlines
Cheapest • from $221 (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
Most popular
Insights
Insights
Insights
Insights
Top layover airports
Cheapest • Avg $225 (round-trip)
Shortest trip • 5h 50m (one-way)
Insights
Insights
Insights
Insights
When to travel
Cheapest • 35% 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

Sat, Sep 12 - Tue, Sep 15
Frontier Logo
11:06 am - 11:55 pm
ORD
-
ONT
14h 49m
1 stop
Frontier Logo
6:00 am - 9:35 pm
ONT
-
ORD
13h 35m
1 stop
$221Frontier
Tue, Jul 28 - Sat, Aug 1
Frontier Logo
9:57 pm - 10:04 am
ORD
-
ONT
14h 07m
1 stop
Frontier Logo
6:00 am - 8:52 pm
ONT
-
ORD
12h 52m
1 stop
$231Frontier
Wed, Aug 19 - Sat, Aug 29
Southwest Logo
5:25 pm - 7:35 pm
MDW
-
ONT
4h 10mnonstop
Southwest Logo
11:55 pm - 5:45 am
ONT
-
MDW
3h 50mnonstop
$239Southwest
Wed, Aug 19 - Sat, Aug 29
United Airlines Logo
8:06 pm - 10:35 pm
ORD
-
ONT
4h 29mnonstop
United Airlines Logo
7:00 am - 1:10 pm
ONT
-
ORD
4h 10mnonstop
$239United Airlines
Thu, Aug 6 - Tue, Aug 11
Frontier Logo
9:27 pm - 8:41 am
MDW
-
ONT
13h 14m
1 stop
Frontier Logo
8:17 am - 4:51 pm
ONT
-
MDW
6h 34m
1 stop
$240Frontier
Tue, Aug 4 - Sat, Aug 8
Frontier Logo
9:34 pm - 8:41 am
ORD
-
ONT
13h 07m
1 stop
Frontier Logo
6:00 am - 8:52 pm
ONT
-
ORD
12h 52m
1 stop
$240Frontier
Sat, Aug 22 - Sat, Aug 29
Frontier Logo
2:41 pm - 11:50 pm
ORD
-
ONT
11h 09m
1 stop
Frontier Logo
7:56 pm - 1:36 pm
ONT
-
ORD
15h 40m
1 stop
$241Frontier
Wed, Jul 29 - Wed, Aug 5
United Airlines Logo
8:18 pm - 10:51 pm
ORD
-
ONT
4h 33mnonstop
United Airlines Logo
1:50 pm - 12:59 am
ONT
-
ORD
9h 09m
1 stop
$245United Airlines
Wed, Aug 19 - Sat, Aug 29
Southwest Logo
6:00 am - 12:30 pm
MDW
-
ONT
8h 30m
1 stop
Southwest Logo
11:55 pm - 5:45 am
ONT
-
MDW
3h 50mnonstop
$249Southwest
Sat, Nov 7 - Wed, Nov 11
Delta Logo
11:35 am - 7:32 pm
MDW
-
ONT
9h 57m
1 stop
Delta Logo
10:59 pm - 9:52 am
ONT
-
MDW
8h 53m
1 stop
$259Delta
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 September.

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 $268 on the route between Chicago Midway Airport (MDW) and Ontario (ONT). The most popular route is between Chicago Midway Airport (MDW) 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 December, where tickets cost $107 (return) on average. On the other hand, the most expensive months are June and May, where the average cost of round-trip tickets is $210 and $208 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.

No, with an average price for the route of $500, prices are generally cheapest when you fly direct.

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$98
Best time to beat the crowds but there is an average 25% increase in price.
Most popular time to fly with an average 22% increase in price.
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 5 days, the lowest price for a flight from Chicago to Ontario was $98 for a one-way ticket and $221 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, Alaska Airlines, and JetBlue 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 $534 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 $521 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 $203 or less one-way and $395 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 4250 reviews
7.5Entertainment
8.1Boarding
8.0Comfort
8.6Crew
7.0Food
Airline reviews

It was just okay, no frills, basic transportation with no luxury. No screens on the seats, no water or drinks on a short flight. Full flight but at least it was on time.

6.0 GoodSteven, Jun 2026
LAS - ONT
Read more Southwest reviews

It was just okay, no frills, basic transportation with no luxury. No screens on the seats, no water or drinks on a short flight. Full flight but at least it was on time.

OKay. I sat in the back of the plane and it was really loud between babies and little kids, and adults who.like to talk a lot and loudly most of the flight.

The first time I flew in the extra legroom section. It was difficult to notice a difference. I had bad luck with my neighbors. The crew was okay. Southwest has reduced the live TV options.

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.

The staff was very friendly, professional, and courteous. The overall flight was a great experience.

Plane crashed into a bus or some other vehicle on the ground while pulling out of the gate. No injuries, but wing tip was damaged and returned to gate for “maintenance issues” and we departed 5 hours later because the plane went out of service and new plane was flown in from a nearby airport, Midway.

Flight was delayed more than 2 hour do the scheduling issues and then some confusing weight and balance matters, followed by a miscommunication with the tower on which runway was going to be used based on the airplane weight. All these things should have been figured out in advance. Instead of arriving at 12:30 a.m. we arrived at 2:30 a.m. very difficult to find a taxi or other transport at SFO. Luggage was delayed. An extension of an unpleasant flight day

Our flight to Oakland was great bc the plane was new but it was delayed by 15min not bad at all. Over all it was an 8/10

The flight in it self was good. The delays looking for pilots was unexpected.

no entertainment options available on a 4+ hour flight. packed in like sardines. one bathroom. late flight.

Know that the movies that you are going to be offered are the oldest be rated movies they could possibly get. They may have one or two new movies that they keep advertising but when you’re flying 15 hours, there is nothing to see past the first new movie.

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.

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

Subject: Formal Complaint: Discriminatory and Unprofessional Conduct – Request for Immediate Action & Compensation Dear [Airline Customer Relations Team], I am writing to file a formal complaint regarding my recent travel experience with [Airline], which was by far the worst I have ever encountered. What occurred was not only unprofessional, but in several instances discriminatory, unsafe, and unacceptable. On the first leg of my trip, I arrived only four minutes past check-in. Instead of making any attempt to resolve the matter, your representative flatly denied me boarding and made me wait while she attended to passengers who arrived after me. By the time a manager intervened, it was too late to board, costing me time, money, and unnecessary frustration. The second leg of my trip (Chicago–San Francisco) raised even more serious concerns. From the outset, it was apparent that the staff—particularly two attendants—prioritized Caucasian passengers while dismissing African American and minority passengers. • When a Caucasian passenger in the exit row refused to comply with federal safety requirements, I, as a first responder, immediately offered to switch seats and assume the responsibility. My offer was blatantly ignored, and instead, a Caucasian passenger seated further up was chosen. This was discriminatory and deeply insulting, especially as I was actively de-escalating the situation that could have delayed the flight further. • During a lengthy tarmac delay of over 90 minutes, passengers were given conflicting and unreasonable instructions that created unnecessary distress and tension. • Throughout the flight, a visibly intoxicated passenger directly in front of me was disruptive, rude to others, failed to comply with seatbelt and electronic device rules, and yet faced no enforcement from the crew. In stark contrast, I was singled out for repeated compliance checks even though I was following every rule. This unequal treatment was so obvious that multiple passengers around me spoke up in my defense. This pattern of behavior demonstrated a clear lack of professionalism, disregard for passenger safety, and discriminatory treatment. I expect far better from an airline of your stature. As a paying customer subjected to this unacceptable treatment, I am formally requesting: 1. A full investigation into the conduct of the staff on both flights. 2. A written apology acknowledging the discriminatory and unprofessional behavior I endured. 3. Appropriate compensation for the distress, inconvenience, and mishandling of my travel. If this matter is not addressed promptly and thoroughly, I will have no choice but to escalate my complaint further, including filing with the U.S. Department of Transportation and sharing my experience through other channels. I trust [Airline] will take this complaint seriously and provide a timely resolution.

Check in was quick and easy during early hours. Flight was on time, and customer services was a plus.

A bit rush for transit. Food and entertainment are not available

We arrived early and finally made it to our gate almost an hour after.

Was a pain having to leave the plane and reboard but glad the plane was fixed

Airline did not explain reasons why flight was delayed two hours. Explanations were badly needed and rarely provided. Problem seemed to clearly be the airline’s fault and not the fault of the weather or airport.

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 !!!!!!!

Better than expected. Staff were friendly and nice on both flights.

Just know that everything, and I mean everything is “ala cart”. 60$ just to put something in the overhead bin. I will never fly Frontier again nor do I recommend them to anyone else.

Great for the price. No wifi or entertainment, but gate agents and crew were fantastic and we boarded quickly and left on time.

The crew was mostly okay. The flight attendant who answered our questions was curt and unhelpful unfortunately. He seemed upset and I understand having off days.

Our flight was canceled for no known reason. We weren’t told until we were checking in at 5:00 am. This was after our last flight with Frontier where we sat on the plane for three hours (not an exaggeration) before we took off because of a mechanical issue. We won’t be flying Frontier again.

Flight was cancelled and was not able to get another flight thru Frontier. Per frontier a refund was issued but I do not see a refund on my Afirm account.

The agent at check-in was strident, unwelcoming, and condescending to customers ahead of me.

Was charged 99 dollars for a bag despite agents previously telling me it would be ok. Customer service was unhelpful

I will like you ( Frontier Airlines) to fly into LAX instead of ONT because I live in LA and the subway takes me to my house in just 15 minutes

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

Information on your arrival and departure airports