$29 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 12/3. 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 York1 stop$193
Los Angeles
Los Angeles1 stop$127
Las Vegas
Las Vegasnonstop$57
Miami
Miami1 stop$130
Chicago
Chicago1 stop$162
San Francisco
San Franciscononstop$77
Boston
Boston1 stop$294
Washington, D.C.
Baltimore1 stop$167
Denver
Denvernonstop$91
Seattle
Seattlenonstop$132
Fort Lauderdale
Fort Lauderdale1 stop$154
Atlanta
Atlanta1 stop$167
Dallas
Dallas1 stop$143
Tampa
Tampa1 stop$130
Houston
Houston1 stop$114
Honolulu
Honolulu1 stop$388
San Diego
San Diego1 stop$133
Philadelphia
Philadelphia1 stop$134
New York
New York1 stop$193
Los Angeles
Los Angeles1 stop$127
Las Vegas
Las Vegasnonstop$57
Miami
Miami1 stop$130
Chicago
Chicago1 stop$162
San Francisco
San Franciscononstop$77
Boston
Boston1 stop$294
Washington, D.C.
Baltimore1 stop$167
Denver
Denvernonstop$91
Seattle
Seattlenonstop$132
Fort Lauderdale
Fort Lauderdale1 stop$154
Atlanta
Atlanta1 stop$167
Dallas
Dallas1 stop$143
Tampa
Tampa1 stop$130
Houston
Houston1 stop$114
Honolulu
Honolulu1 stop$388
San Diego
San Diego1 stop$133
Philadelphia
Philadelphia1 stop$134

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

Mon, Jan 5 - Mon, Jan 12
Frontier Logo
6:00 am - 7:07 amONT-LAS
1h 07mnonstop
Frontier Logo
8:13 pm - 9:17 pmLAS-ONT
1h 04mnonstop
$57Frontier
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Wed, Jan 21 - Fri, Jan 23
Frontier Logo
8:30 am - 9:36 amONT-LAS
1h 06mnonstop
Frontier Logo
8:13 pm - 9:17 pmLAS-ONT
1h 04mnonstop
$58Frontier
Find Deal
Wed, Dec 3 - Sat, Dec 6
United Airlines Logo
1:50 pm - 3:14 pmONT-SFO
1h 24mnonstop
United Airlines Logo
4:16 pm - 5:37 pmSFO-ONT
1h 21mnonstop
$77United Airlines
Find Deal
Fri, Jan 30 - Mon, Feb 2
United Airlines Logo
1:24 pm - 4:43 pmONT-DEN
2h 19mnonstop
United Airlines Logo
7:34 pm - 8:58 pmDEN-ONT
2h 24mnonstop
$117United Airlines
Find Deal
Fri, Dec 12 - Sun, Dec 14
Southwest Logo
4:40 pm - 11:00 pmONT-HOU
4h 20m1 stop
Southwest Logo
2:05 pm - 3:35 pmHOU-ONT
3h 30mnonstop
$139Southwest
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Thu, Dec 11 - Tue, Jan 6
Delta Logo
6:00 am - 12:57 pmONT-SEA
6h 57m1 stop
Delta Logo
9:25 am - 4:13 pmSEA-ONT
6h 48m1 stop
$139Delta
Find Deal
Sat, Dec 6 - Sun, Dec 7
Delta Logo
4:49 pm - 11:25 pmONT-SEA
6h 36m1 stop
Delta Logo
7:11 pm - 11:58 pmSEA-ONT
4h 47m1 stop
$140Delta
Find Deal
Fri, Dec 5 - Sun, Dec 7
Southwest Logo
3:30 pm - 10:05 pmONT-HOU
4h 35m1 stop
Southwest Logo
2:05 pm - 3:35 pmHOU-ONT
3h 30mnonstop
$143Southwest
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Thu, Dec 4 - Tue, Dec 9
American Airlines Logo
4:47 pm - 11:31 pmONT-IAH
4h 44m1 stop
American Airlines Logo
2:22 pm - 6:19 pmIAH-ONT
5h 57m1 stop
$187American Airlines
Find Deal
Thu, Dec 4 - Tue, Dec 9
American Airlines Logo
11:59 pm - 8:32 amONT-HOU
6h 33m1 stop
American Airlines Logo
5:44 am - 9:54 amHOU-ONT
6h 10m1 stop
$187American Airlines
Find Deal
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 $38 round-trip. The most popular route is from Ontario (ONT) to Las Vegas (LAS), and the cheapest round-trip airline ticket found on this route in the last 72 hours was $38.

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 $313, 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 January, when tickets cost $259 (return) on average. On the other hand, the most expensive months are December and April, when the average cost of round-trip tickets is $445 and $366 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 Saturday 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 Mondays.

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 29% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 4 weeks before departure.

Good to know

Low seasonFebruary
Cheapest flight$29
Best time to beat the crowds with an average 7% drop in price.
Most popular time to fly with an average 8% increase in price.
Flight from Ontario to Las Vegas

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 
FraxysFlew with American AirlinesONT-DFWJun 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 FrontierONT-LASDec 2024
Pack light and arrive earlier.. Also download the App and check your flight and check in..
LeoFlew with American AirlinesONT-CLTSep 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 AirlinesONT-PDXOct 2024
Portland is a big airport, give yourself time.
MariFlew with American AirlinesONT-CLTJan 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.

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

    The cheapest time of day to fly to the United States is generally in the evening, when round-trip flights cost $309 on average. Morning departures are around 100% cheaper than evening flights, 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 $359.

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 $109 one-way - $182 round-trip; Dallas $162 one-way - $267 round-trip; Las Vegas $86 one-way - $119 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.
8.0
SouthwestOverall score based on 4239 reviews
7.5Entertainment
8.0Comfort
8.6Crew
7.0Food
8.1Boarding
Airline reviews

Ever since Southwest starting charging for bags, passengers don't want to pay to check their bags, so the gate agents have to beg people to check their roller bags now because there's "not enough space". This was a terrible business move by Southwest.

8.0 ExcellentGreg, Oct 2025OAK - BUR
Read more Southwest reviews

Ever since Southwest starting charging for bags, passengers don't want to pay to check their bags, so the gate agents have to beg people to check their roller bags now because there's "not enough space". This was a terrible business move by Southwest.

Sacrament staff are always polite and helpful. Airport is easy to maneuver and boarding is straightforward.

As always, the entire Southwest experience was wonderful, from online booking to flight to baggage retrieval. Very grateful.

The weather could have been better. There was a 40 minute ATC delay in SFO because of marine fog and a micro cell storm delayed landing and take-off at Nashville. The gate was changed 5 minutes from boarding from gate B3 to gate C23 at Nashville airport.

The cabin was quiet for the redeye flight. The area was clean. The staff was great. The 787 Max was in good condition. Drawbacks were that the seat widths were tight for some passengers. The seat padding was at best average and for a long flight uncomfortable.

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

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!

Staff were friendly and happy. Delta could make sure passengers that don't have the app know of changes. Without Kayak I would not have known about the change of gate or the delay. Kayak was faster to notify me.

The flight used a B767 with a very old interior from before 2014. The entertainment system did not work at all during the flight despite attempts to reset the system. It was like they flew this route just to be competitive.

Delayed flight (1hour) plus a long layover after an overnight flight with no backup plane available.

Flight delayed for two and half hours and then canceled altogether due to mechanical issues. No mechanic onsite to fix so had to send one from LAX.

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.

Premium Plus is a really good idea for longer flights

The flight attendants were great, I joked with one I can’t remember her name, a blond, really sweet. I thought it was run well very professional. This was great i survived Spirit, I know for which I speak.

I was in first class. The outlets at my seat did not work. The plane was shabby and run down. I had prepurchsed a day subscription for internet that was not redeemable. I had to repurchase the internet for my flight and then it didn’t work anyway. Quite disappointed in what was supposed to be the launch of a great vacation.

I understand stuff happens, but plane failures are likely due to lack of maintenance. Additionally, air conditioning wasn't working, no snack/drink service, no WiFi. Fortunately, the crew was communicative and light-hearted. United grabbed another plane and we were able to get to our destination.

Stuck on tarmac for two hours plus a 5.5 hour flight. Rude flight attendant. And no meals, not even for purchase!

I learned that seating towards the end of plane that a line forms for the restroom and people use your chair as a hand railing, bumping your seat consistently. I was seated in the aisle. I think that next time if I am towards the back row I would want to sit in the middle or window seat.

United sent me a mileage plus number last year but that number is invalid so I can’t use it to check into flights or collect mileage. There is human to speak about the problem, only computers who keep asking me if I am using the correct email. It’s so frustrating and I cannot resolve it.

Not a great experience. We paid for the upgrade for premium economy seats and seated ourselves in very comfortable seats. Someone came along with the same seat on their boarding pass. The aircraft had been changed and as a result we were booted out and sent further back to small uncomfortable seats. After complaining we were moved to emergency row seats, which gave us more leg room but the seats don’t recline. For people in our 70’s we found having to sit upright from California to NJ very uncomfortable. Not sure why they chose to move senior citizens instead of the two people that were allowed to take the more comfortable seats. Not happy.

Everything was great. Only thing that could’ve made it better was buy on board options for hot food, but the snacks were decent. The flight attendants were great. I had no complaints. I was able to make it to my destination safely

Boarded plane and then delayed 1.5 hours while on the plane

The flight was smooth, the pilot kept us informed about delays and we arrived more of less on time

The flight was flawless and we even arrived between 20 and 25 minutes early!

Always seated jammed in rear of aircraft Admirals Club food at DFW terminal D was absolute worst food experience and I pay $600/year to eat this dried out junk

Mostly good. Flight was crowded but Airline personnel were very friendly & accommodating. It would be good to have savory snacks rather than just sweet Biscoff cookies.

It was a red eye flight, so no meals were provided, but it was fine with snacks. The seats felt cramped and almost too narrow.

Very crowded flight but what can you expect these days?? Crew was accommodating.

The seats in economy were appeared to be quite thin and lack sufficient cushioning to be comfortable. Perhaps it was my seating position but the plane seemed notably load.

The entertainment package was vast and the selections were very current. Keep updating it was great.

The seat was so hard my tailbone was aching The crew was kind of a b**** because I made a joke that I didn't care if they close the door I total c*** when she was trying to f****** act like she was mad at me because I said that The flight was bumpy. Sure you didnt have control over that.

4 hours late, including over +1 hour waiting in plane to take off. Baggage left behind too.

Terrible. Flight cancelled with no reasoning and no flights to rebook. Employees were useless and did nothing to help. Did not even know where to retrieve luggage from the cancelled flight. Flyers beware.

No fault of Frontier staff: plane was very late, reached Orlando at 1 am, took a while to get luggage. Weather, gov financial shutdown impact on TSA, air controllers seemed to have multiple flights backed up. Frontier staff seemed to cope as gracefully as possible. It did reassure me that I and my new hip could adapt to travel challenges. Food/entertainment were irrelevant to my trip.

Terrible. The canceled my entire flight when I requested a refund for a trip frontier canceled trip one way.

This airline sucks. They offer low rates then charge you for everything, the app does not work well, the seats are the most uncomfortable. Maintenance issues on the flight, and you still have to sit through their credit card commercials. People are nice enough but does not make up for overall poor experience.

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 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

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

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