$36 Find Cheap Flights from Ontario to the United States

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 the United States 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

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Flight Deals

Cheap Flights from Ontario to the United States

Cheapest round-trip prices found by our users on KAYAK in the last 72 hours
New York
New York2 stops$282
Los Angeles
Los Angeles1 stop$126
Las Vegas
Las Vegasnonstop$73
Chicago
Chicago1 stop$278
San Francisco
San Franciscononstop$106
Miami
Miami1 stop$230
Boston
Boston1 stop$292
Fort Lauderdale
Fort Lauderdale1 stop$190
Denver
Denvernonstop$105
Seattle
Seattlenonstop$139
Atlanta
Atlanta1 stop$286
Dallas
Dallas1 stop$201
Tampa
Tampa1 stop$180
Houston
Houstonnonstop$144
San Diego
San Diego1 stop$126
Honolulu
Honolulu2 stops$397
Philadelphia
Philadelphia1 stop$179
New York
New York2 stops$282
Los Angeles
Los Angeles1 stop$126
Las Vegas
Las Vegasnonstop$73
Chicago
Chicago1 stop$278
San Francisco
San Franciscononstop$106
Miami
Miami1 stop$230
Boston
Boston1 stop$292
Fort Lauderdale
Fort Lauderdale1 stop$190
Denver
Denvernonstop$105
Seattle
Seattlenonstop$139
Atlanta
Atlanta1 stop$286
Dallas
Dallas1 stop$201
Tampa
Tampa1 stop$180
Houston
Houstonnonstop$144
San Diego
San Diego1 stop$126
Honolulu
Honolulu2 stops$397
Philadelphia
Philadelphia1 stop$179

Book Cheap Ontario to the United States 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 the United States 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 the United States

Tue, Aug 11 - Thu, Aug 13
Frontier Logo
1:28 pm - 2:39 pm
ONT
-
LAS
1h 11mnonstop
Frontier Logo
6:46 pm - 7:53 pm
LAS
-
ONT
1h 07mnonstop
$73Frontier
Sat, May 30 - Mon, Jun 1
Frontier Logo
3:30 pm - 4:43 pm
ONT
-
LAS
1h 13mnonstop
Frontier Logo
1:59 pm - 3:09 pm
LAS
-
ONT
1h 10mnonstop
$75Frontier
Wed, May 27 - Tue, Jun 2
Southwest Logo
9:55 pm - 9:40 am
ONT
-
HOU
9h 45m
1 stop
Southwest Logo
9:00 pm - 10:25 pm
HOU
-
ONT
3h 25mnonstop
$267Southwest
Tue, Jun 2 - Tue, Jun 9
American Airlines Logo
10:00 pm - 10:33 am
ONT
-
JFK
9h 33m
1 stop
American Airlines Logo
2:43 pm - 9:57 pm
JFK
-
ONT
10h 14m
2 stops
$282American Airlines
Tue, Jun 2 - Tue, Jun 9
American Airlines Logo
11:59 pm - 1:48 pm
ONT
-
JFK
10h 49m
2 stops
American Airlines Logo
2:43 pm - 9:57 pm
JFK
-
ONT
10h 14m
2 stops
$287American Airlines
Sat, May 30 - Sat, Jun 6
United Airlines Logo
6:30 am - 12:45 pm
ONT
-
ORD
4h 15mnonstop
United Airlines Logo
8:18 pm - 10:51 pm
ORD
-
ONT
4h 33mnonstop
$287United Airlines
Sat, Jun 6 - Tue, Jun 9
United Airlines Logo
6:05 am - 12:20 pm
ONT
-
ORD
4h 15mnonstop
United Airlines Logo
8:18 pm - 10:51 pm
ORD
-
ONT
4h 33mnonstop
$288United Airlines
Mon, Jun 1 - Sat, Jun 6
Southwest Logo
3:00 pm - 12:05 am
ONT
-
HOU
7h 05m
1 stop
Southwest Logo
9:20 pm - 10:30 pm
HOU
-
ONT
3h 10mnonstop
$297Southwest
Fri, Sep 18 - Wed, Sep 23
Alaska Airlines Logo
7:20 am - 10:22 am
ONT
-
HNL
6h 02mnonstop
Alaska Airlines Logo
12:43 pm - 9:20 pm
HNL
-
ONT
5h 37mnonstop
$400Alaska Airlines
Tue, Aug 18 - Fri, Aug 21
Alaska Airlines Logo
9:11 am - 12:09 pm
ONT
-
HNL
5h 58mnonstop
Alaska Airlines Logo
12:43 pm - 9:20 pm
HNL
-
ONT
5h 37mnonstop
$402Alaska Airlines
Booking Insights

KAYAK's insights & trends for Ontario to the United States flights

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

What is the cheapest Ontario to the United States flight route?

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

The cheapest ticket to the United States from Ontario found in the last 72 hours was to Las Vegas, at $58 round-trip. The most popular route is from Ontario (ONT) to Dallas/Fort Worth Airport (DFW), and the cheapest round-trip airline ticket found on this route in the last 72 hours was $226.

What is the cheapest time of day to fly to the United States?

The average price for all round-trip flights from Ontario to the United States depending on the time of departure, clicked by users on KAYAK in the last 2 weeks.

The cheapest time of day to fly to the United States is generally at night, when round-trip flights cost $372 on average. The most expensive time of day to fly to the United States is generally at night, which is peak travel time and where the average cost of a ticket is $372.

Can I save money by flying with a layover from Ontario to the United States?

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 $361, prices are generally cheapest when you fly direct.

What is the cheapest month to fly from Ontario to the United States?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Ontario to the United States, 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 the United States is August, when tickets cost $269 (return) on average. On the other hand, the most expensive months are March and June, when the average cost of round-trip tickets is $389 and $346 respectively.

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

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

When flying from Ontario to United States, you should consider leaving on a Sunday and avoid Thursdays if you are looking for the best rates. For your return to Ontario, you’ll find the best rates on Fridays and the most expensive ones on Sundays.

How far in advance should I book a flight from Ontario to the United States?

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 the United States, 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 the United States, you should book around 2 weeks before departure, which saves you about 28% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 4 weeks before departure.

Good to know

Low seasonJanuary
Cheapest flight$59
Most popular time to fly and prices are also 3% lower on average.
Flight from Ontario to Chicago O'Hare Airport

Flights from Ontario to the United States: the best tips from KAYAK users

Insights shared by verified travelers who flew the route from Ontario to the United States 
Verified travelerFlew with Alaska Airlines
ONT
-
PDX
Mar 2026
TSA security isn’t bad, sometimes gets crowded right before another flight goes out. Smaller airport but has many flight options.
AdrianaFlew with American Airlines
ONT
-
PHX
Apr 2026
Check on your flight status often, as things can change and you may not be notified promptly
Verified travelerFlew with United Airlines
ONT
-
SFO
Feb 2026
1 hr is doable if you're transferring at sfo but probably just get something to go food wise
FraxysFlew with American Airlines
ONT
-
DFW
Jun 2025
Bring an empty refillable water bottle/container through TSA and fill it up as soon as you pass the security check. The water station is available to the left and to the right of it.
Verified travelerFlew with Frontier
ONT
-
LAS
Dec 2024
Pack light and arrive earlier.. Also download the App and check your flight and check in..
LeoFlew with American Airlines
ONT
-
CLT
Sep 2024
Have plenty of patience for the casual travelers! They are oblivious of rules and etiquettes that slows down the process for everyone. Case in point, a guy held up the line trying to place both his personal item (should be UNDER the seat in front of you) and his carry on case horizontally. Obviously not aware of the big poster right in front of his displaying the proper way of placing his case on it's side. Slowed the whole line of people behind him. Also be mindful the agents in Ontario airport (or any smaller airports) might not be the most knowledgeable on the rules and regulations of air travel, luggage specification allowances etc. Stay patient!! Also the seats do not recline that well anymore on AA flights. So if you have back problems, be sure to bring some back supports.
Verified travelerFlew with Alaska Airlines
ONT
-
PDX
Oct 2024
Portland is a big airport, give yourself time.
MariFlew with American Airlines
ONT
-
CLT
Jan 2024
Bring a blanket it's very cold on plane

FAQs - booking United States flights

  • How does KAYAK find such low prices on flights from Ontario to the United States?

    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 the United States.

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

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

    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 the United States 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 the United States?

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

Top tips for finding cheap flights to the United States

  • Looking for a cheap flight? 25% of our users found tickets from Ontario to the following destinations at these prices or less: Denver $132 one-way - $234 round-trip; Dallas $154 one-way - $315 round-trip; Las Vegas $123 one-way - $158 round-trip

Reviews of the top 5 airlines serving from Ontario to the United States

 
Need help choosing which airline to fly with from Ontario to the United States? 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
Alaska AirlinesOverall score based on 12325 reviews
7.0Entertainment
8.5Crew
7.1Food
7.8Comfort
8.1Boarding
Airline reviews

I had to cancel my trip due to medical reasons. I have been unable to cancel online through either Kayak or Alaska Airlines.. I am trying to get my insured trip reimbursed by XCover. They are requiring a notice of cancellation or not using to get my refund. Please help me get that information. I have been unable to get this information from either Kayak or Alaska Airlines.

2.0 MediocreDave, May 2026
PSP - SEA
Read more Alaska Airlines reviews

I had to cancel my trip due to medical reasons. I have been unable to cancel online through either Kayak or Alaska Airlines.. I am trying to get my insured trip reimbursed by XCover. They are requiring a notice of cancellation or not using to get my refund. Please help me get that information. I have been unable to get this information from either Kayak or Alaska Airlines.

Alaska is by far the best airline to fly with 😍

They were flexible and able to get me home a day earlier due to a family members illness. Flight was on time and great friendly crew.

Affirmed my disability by allowing me to board when most accessible. Very parable, helpful and friendly staff. Smooth flight overall! I always fly Alaska when possible! Thank you!

Agent could not provide me a boarding pass for the second leg of my flights - yet with a partner airline. Not understood.

I had to change my flight last minute due to a medical emergency. Their agent was compassionate and extremely helpful. This airlines really cares about making travel, for fun, work, or an emergency a customer-focused experience. Thank you!

More efficient with checking lines and boarding/checking bags when needed.

They were really helpful with every question and my kids had never been on a plane and the staff made them feel comfortable

The flight would have been very good , if not dor the constantly screaming baby in the row behind me. Is there a way to isolate people traveling with infants? This is not the first time this has happened to me.

No headphones provided. No gf food. Only 1 beverage cart run sAN to HNL. Rarely saw crew members

The entire experience from boarding to landing was amazing! The crew were very friendly. Will definitely be back.

Delayed flight, lack of information, boarding process is a mess as is the carryon luggage causing issues when leaving the plane….just a poor experience.

Comfortable. Easy. No problems. Just wish they had gf options for snacks.

The crew was very kind and made going to Hawaii relaxing and fun to look forward to! Thank you Southwest for a pleasant flight!

Terrible. Even though there’s assigned seating now, they are still the slowest boarding airline of anyone.

It was good from LAX to Phoenix, But the connection in Phoenix to Tulsa was not that great. The staff on both flights were great. The choice of free entertainment was ok nothing to brag about. The 45 min delay because of some electrical issue wasn't great from Phoenix to Tulsa. We sat there with hardly any air, The seat I had was between windows so the side of the plane pushed in on you. My being a bigger man it then made the seating area uncomfortable. The seats on the plane had no power to connect to recharge your phone or anything. I would recommend that they should look into a slot or clamp to hold your phone to enjoy while watching the entertainment choices hands-free. Also make it possible to raise the inner seat by the window be able to raise the arm rest up to make more room for larger people to set more comfortably. I would also say other then that stop price gouging the airfare or nickel and diming everything. Not fair for people having to fly for emergencies and be paying for higher prices due to the season or holidays. Your making your money either way and the cost of flying is still going to be the same regardless if there's 100 people or 200 people.

Southwest was greaat! The most expensive but the least upsetting for those we were flying to see.

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.

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

Booked through Kayak Business, had a seat in middle and towards back due to booking rate, not comfortable.

Outstanding service, efficient & friendly crew, flight was safe, comfortable & on time

It was a red-eye, but the flight felt surprisingly quick. The seats were very comfortable, and that made resting much easier. I also want to thank the gentleman seated next to me, who graciously moved so my mom could sit beside me. We slept almost the entire way. The cabin crew was respectful in not disturbing us, while also being courteous and professional throughout. Thank you, United.

Boarding was again a "free for all". We were boarding group 4, and almost the entire plane was able to board before us. It's a shame that someone who follows the rules, gets the short end of the stick. Not fair.

It was perfect! I've never flown with United before, but I definitely will in the future

I had a cancelled flight because of technical issues going to my destination, and a delayed flight coming home. All told it wasn’t a total bust.

They delayed the flight from 9:00 to 11:55 At 11:45 they canceled the flight. I paid a premium price for the tickets with poor service

My flight was canceled a few hours before boarding. I was rebooked on Copa airlines and missed an important meeting .

OK, we were delayed and had to de plane and reboard.

Seats are uncomfortable. This has been a trend in the industry for decades. Trying to fit more seats on each plane to increase profits at the expense of the passenger.

Left early arrived early..right amount of talking from pilots..of course had to love the biscuit and water!

Boarding gate at LAX was too crowded—two gates next to one another

On time departure and early arrival. Flight attendant very nice.

The SFO Lounge crew were amazing. The bartender Faris was great. Thanks!

Was not able to do a online check-in because the American Airlines system doesn't store our visa or other passport information, allowing us to have a trouble-free check-in. We were forced to have to check-in at the counter which Changes are upgrade status given that we were not able to check in much earlier.

Good flight, seated and had a water within 5 minutes. Crew was hospitable.

We left at 1030 am pacific from LA and supposed to land at 7 pm Eastern in NY. They made a detour, stopped in Philadelphia and didn’t land till 1130 PM Eastern!!! Worst flight experience with no pilot communication with no explanation as to what was going on. Everyone was very frustrated to say the least.

Flight boarded from Gate 159B, the farthest gate in the LAX Bradley Terminal. While the flight operated on time, the first class cabin attendant made no recognition of my being an Advantage Executive Platinum member.

The flight itself was excellent but the gate attendant made me check my carryon since she said it was an inch too big. I’ve had no problems with this carryon on recent flights on Qantas, Delta, Austrian, Southwest Airlines even though the overhead bins are the same size. there were other carryons in the bins that also looked larger than mine and there was room left in the bins for more. When I picked up my carryon from baggage claim one of the wheels had broken off.

I was in last row so that is never great bc the person in front of me leaned his seat all the way back into me.

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.

Remind customers of the need to have passport or new ID for boarding.

The flight never took off and we spent 7 hours at the airport

Everything you need to know for your flight from Ontario to the United States

Information on your arrival and departure airports