$19 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 8/10. 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

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Best United States Flight Deals from Ontario

Cheapest round-trip prices found by our users on KAYAK in the last 72 hours
New York
New York1 stop$146
Los Angeles
Los Angeles1 stop$487
Las Vegas
Las Vegasnonstop$53
Miami
Miami1 stop$124
Chicago
Chicago1 stop$133
San Francisco
San Franciscononstop$38
Boston
Boston1 stop$264
Denver
Denvernonstop$93
Seattle
Seattlenonstop$115
Fort Lauderdale
Fort Lauderdale2 stops$275
Atlanta
Atlanta1 stop$117
Dallas
Dallas1 stop$99
Tampa
Tampa1 stop$153
Houston
Houston1 stop$118
Honolulu
Honolulu1 stop$337
San Diego
San Diego1 stop$133
Philadelphia
Philadelphia1 stop$161
New York
New York1 stop$146
Los Angeles
Los Angeles1 stop$487
Las Vegas
Las Vegasnonstop$53
Miami
Miami1 stop$124
Chicago
Chicago1 stop$133
San Francisco
San Franciscononstop$38
Boston
Boston1 stop$264
Denver
Denvernonstop$93
Seattle
Seattlenonstop$115
Fort Lauderdale
Fort Lauderdale2 stops$275
Atlanta
Atlanta1 stop$117
Dallas
Dallas1 stop$99
Tampa
Tampa1 stop$153
Houston
Houston1 stop$118
Honolulu
Honolulu1 stop$337
San Diego
San Diego1 stop$133
Philadelphia
Philadelphia1 stop$161

Cheap Flights from Ontario to the United States

 
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, Jul 21 - Mon, Jul 28
Frontier Logo
9:41 pm - 11:14 pmONT-SFO
1h 33mnonstop
Frontier Logo
10:11 pm - 11:40 pmSFO-ONT
1h 29mnonstop
$38Frontier
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Mon, Jul 21 - Mon, Jul 28
Frontier Logo
9:41 pm - 11:14 pmONT-SFO
1h 33mnonstop
Frontier Logo
10:11 pm - 11:40 pmSFO-ONT
1h 29mnonstop
$45Frontier
Find Deal
Tue, Jul 29 - Tue, Jul 29
United Airlines Logo
6:39 pm - 8:06 pmONT-SFO
1h 27mnonstop
United Airlines Logo
9:25 pm - 10:52 pmSFO-ONT
1h 27mnonstop
$52United Airlines
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Mon, Jul 21 - Thu, Jul 24
United Airlines Logo
6:39 pm - 8:06 pmONT-SFO
1h 27mnonstop
United Airlines Logo
9:25 pm - 10:52 pmSFO-ONT
1h 27mnonstop
$57United Airlines
Find Deal
Tue, Aug 26 - Thu, Aug 28
Southwest Logo
5:45 am - 6:50 amONT-LAS
1h 05mnonstop
Southwest Logo
11:30 am - 4:30 pmLAS-ONT
5h 00m1 stop
$107Southwest
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Tue, Aug 26 - Wed, Aug 27
Southwest Logo
5:45 am - 6:50 amONT-LAS
1h 05mnonstop
Southwest Logo
1:30 pm - 7:50 pmLAS-ONT
6h 20m2 stops
$112Southwest
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Wed, Jul 23 - Tue, Jul 29
Delta Logo
2:14 pm - 5:00 pmONT-SEA
2h 46mnonstop
Delta Logo
10:43 am - 1:34 pmSEA-ONT
2h 51mnonstop
$157Delta
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Mon, Aug 4 - Mon, Aug 11
American Airlines Logo
7:05 pm - 5:35 amONT-EWR
7h 30m1 stop
American Airlines Logo
5:30 am - 9:58 amEWR-ONT
7h 28m1 stop
$268American Airlines
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Tue, Aug 5 - Tue, Aug 12
American Airlines Logo
11:59 pm - 12:36 pmONT-EWR
9h 37m2 stops
American Airlines Logo
12:37 pm - 6:24 pmEWR-ONT
8h 47m1 stop
$272American Airlines
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Tue, Aug 5 - Thu, Aug 7
Delta Logo
11:40 am - 11:04 pmONT-EWR
8h 24m1 stop
Delta Logo
6:00 am - 10:30 amEWR-ONT
7h 30m1 stop
$277Delta
Find Deal
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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?

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

The cheapest ticket to the United States from Ontario found in the last 72 hours was to San Francisco, at $57 round-trip. The most popular route is from Ontario (ONT) to Seattle (SEA), and the cheapest round-trip airline ticket found on this route in the last 72 hours was $156.

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 $641, 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 $277 (return) on average. On the other hand, the most expensive months are December and July, when the average cost of round-trip tickets is $460 and $380 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 Monday and avoid Thursdays if you are looking for the best rates. For your return to Ontario, you’ll find the best rates on Wednesdays and the most expensive ones on Tuesdays.

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. For the absolute cheapest price, our data suggests you should book 10 weeks before departure.


Good to know

Low seasonFebruary
High seasonJuly
Cheapest flight$19
Best time to beat the crowds with an average 5% drop in price.
Most popular time to fly with an average 4% increase in price.
Flight from Ontario to San Francisco

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 $358.

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 $124 one-way - $220 round-trip; Dallas $167 one-way - $305 round-trip; Seattle $121 one-way - $197 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 4266 reviews
8.0Comfort
7.0Food
8.6Crew
7.6Entertainment
8.2Boarding
Airline reviews

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.

4.0 OkayTraci, Jun 2025OAK - SEA
Read more Southwest reviews

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!

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

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

Great flight staff. Ease of boarding. Overall, very uneventful and easy trip.

Employees were kind and funny, as always! Flight was late but no announcements were made for people with tight connections to help them transition quickly. No service due to turbulence.

I recently flew Southwest from San Jose to Honolulu. I was very impressed with the flight crew, especially the flight attendant in charge of the front of the plane. She came through the aisle at least five times for drinks and water, and two times for snacks. I have not seen such service since I flew first class. Also, for the first time, they gave us the correct baggage claim number, and the luggage came out quickly. I can't wait for Southwest to have assigned seating! I absolutely hate the Cattle Call boarding procedure and the mad dash to get seats and overhead bins. However, the boarding was efficient.

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

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

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

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

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

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

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

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

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

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

Boarded plane and then delayed 1.5 hours while on the plane

Horrific. They missed my connecting flight to San Diego. I didn’t get there until Monday at 9am when I had a mandatory court settlement conference scheduled at 6am since we had parties on the east coast. This caused many issues. All because United apparently forgot to hold the doors open until my flight landed that only had a 10 minute delay. This was the last flight to Southern California. So I couldn’t even rent a car to finish the trip. United cannot be trusted when traveling on specific days and times since weather didn’t have anything to do with the delays.

Really good 😊 the woman at the gate entrance was a little rude checking in our carry-on but i dont think she worked for the airline, she worked for the airport at sacramento, other than that amazing.

it was so bad. I tried to board my flight from vancouver to saskatoon. And to my surprise they did not board me cause the flight was changed and no email was send to me. and on my boarding pass which i got from seattle says different flight. I did not knew anyone from Vancouver, air canada crew was rude, i asked for today flight but they were rude and i had early morning dental appointment in saskatoon. I was so much in pain and my whole day is wasted today. and i suffered alot. They did provide me hotel but they did not provide me any food. I am really really disappointed first time had so bad experience with air canada. I may think twice to book it again. If i can get any reply or any composition that would be great. Thanks

Very comfortable (upgraded to business class). The audio on my screen didn’t work, but I managed to play the audio through my phone while watching the screen.

I was supposed to be on business class at first class from Denver back to Miami due to weather changes. I missed my connection and it’s put on a flight to Fort Lauderdale. Instead of honoring my business class/1st class ticket, they put me in coach, but there were two first class seats open. I think it’s absolutely disgusting that I paid for first class $1300 ticket and they put me in economy and they had to open seats available and I have still not been refunded the difference. I ended up having to eat a snack box instead of the meal I was supposed to get and did not get home till 2 AM so I think that’s a little pathetic that I had to live off crackers for dinner And my poor dog ate some cheese and salami. Oh yes, apparently when they switched me to the new flight they forgot to mention I had a service dog

Boarding seemed to be organized bedlam. For what ever reason, preboarding took longer than 20 minutes. Made the plane 20 minutes late taking off. Luckily we arrived on time. Flight crew seemed very friendly. Only slight turbulence.

The personnel were professional and friendly. The Boeing 737 Max 9 is too claustrophobic and was very warm at both airport gates, and still warm in the air.

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

get E+, a must for 5 hours flight if you are tall

AA re-routed flight from HNL to LAX due to delay. My group of 3 with reserved seats in row 9 was broken up, with one assigned to a middle seat, another in the last row of the plane. Not happy. No explanation to the delay. No apologies. No compensation. Would have been nice to be offered an Admiral Club admission or a voucher for the extra 3 hours of layover in LAX. Could not hear the boarding gate announcements in LAX. Adjacent gate was boarding at the same time. Loud speakers were competing against each other. Barely made my boarding group.

Almost a 6 hour flight and the only food option is a cheese plate… and chips. Also how is it there are no options for texting on American. I’ll be going back to delta and united.

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

Cramped seats. FAA should make airlines have more legroom, for even short people complain

Eventless. It was a good flight and good crew. Can’t complaint.

Very helpful ground crew after an earlier flight delay and being rebooked on a different flight.

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

We kept being told that the flight was full and that all overhead compartments were full and therefore had to check in our hand luggage. We were some of the last people to board and noticed that there was still sufficient space in the overhead compartments. We were obliged to check in hand luggage when there was space and so had to wait at luggage retrieval which took a while to then noticed damage to our luggage - not a great experience!

This was an overnight flight. There was no meal service in first class, just a simple snack basket was offered along with beverages. There should have been some type of continental breakfast prior to arrival in PHL. As an Executive Platinum American Airlines Advantage member, I received no name recognition from the first class flight attendant. When disembarking at PHL, the flight attendants were more interested in their cell phones than saying "thank you" to the passengers as they disembarked.

The flight was quick and to the point. The crew just did their job w/o excessive talking and everything was just perfect.

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

They changed the timing , first delayed by 4 hours then went back to 40 mins late, we had to run back to airport to not miss our flight. This is ridiculous

No frills for sure. No gate announcements about flight delay, not even water to drink on the flight.

I loked walking out on the tarmac to board and no first class. I didn't like that they have no snacks or onboard wifi to bide your time.

It was a redeye flight, so every passenger just wanted to sleep, but through the entire flight, the flight crew made announcements over the loudspeaker at maximum volume every few minutes making sleep impossible. For example: it’s 2am, and the crew decides to give an extremely detailed announcement about snacks and beverages for sale. And 3am is the perfect time to wake up everyone with a lengthy announcement about how to get a coffee refill and how to take advantage of new offer from frontier for a credit card.

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

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