$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 10/23. 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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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$225
Los Angeles
Los Angeles1 stop$136
Las Vegas
Las Vegasnonstop$59
Miami
Miami1 stop$158
Chicago
Chicago2 stops$178
San Francisco
San Franciscononstop$77
Boston
Boston1 stop$243
Washington, D.C.
Baltimore1 stop$165
Denver
Denvernonstop$67
Seattle
Seattlenonstop$121
Fort Lauderdale
Fort Lauderdale1 stop$211
Atlanta
Atlanta2 stops$203
Dallas
Dallasnonstop$126
Tampa
Tampa1 stop$153
Houston
Houstonnonstop$105
Honolulu
Honolulu1 stop$375
San Diego
San Diego1 stop$144
Philadelphia
Philadelphia1 stop$164
New York
New York1 stop$225
Los Angeles
Los Angeles1 stop$136
Las Vegas
Las Vegasnonstop$59
Miami
Miami1 stop$158
Chicago
Chicago2 stops$178
San Francisco
San Franciscononstop$77
Boston
Boston1 stop$243
Washington, D.C.
Baltimore1 stop$165
Denver
Denvernonstop$67
Seattle
Seattlenonstop$121
Fort Lauderdale
Fort Lauderdale1 stop$211
Atlanta
Atlanta2 stops$203
Dallas
Dallasnonstop$126
Tampa
Tampa1 stop$153
Houston
Houstonnonstop$105
Honolulu
Honolulu1 stop$375
San Diego
San Diego1 stop$144
Philadelphia
Philadelphia1 stop$164

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

Sat, Sep 27 - Sat, Sep 27
Frontier Logo
8:00 am - 9:11 amONT-LAS
1h 11mnonstop
Frontier Logo
11:27 am - 12:43 pmLAS-ONT
1h 16mnonstop
$59Frontier
Find Deal
Wed, Oct 1 - Wed, Oct 8
Frontier Logo
8:00 am - 9:11 amONT-LAS
1h 11mnonstop
Frontier Logo
7:33 pm - 8:42 pmLAS-ONT
1h 09mnonstop
$62Frontier
Find Deal
Sat, Oct 11 - Sat, Oct 18
United Airlines Logo
6:51 pm - 8:10 pmONT-SFO
1h 19mnonstop
United Airlines Logo
9:30 pm - 10:52 pmSFO-ONT
1h 22mnonstop
$77United Airlines
Find Deal
Fri, Oct 10 - Sat, Oct 18
Southwest Logo
9:35 pm - 10:40 pmONT-LAS
1h 05mnonstop
Southwest Logo
7:45 am - 12:45 pmLAS-ONT
5h 00m1 stop
$86Southwest
Find Deal
Sat, Oct 11 - Sat, Oct 18
Southwest Logo
8:45 pm - 9:50 pmONT-LAS
1h 05mnonstop
Southwest Logo
7:45 am - 12:45 pmLAS-ONT
5h 00m1 stop
$87Southwest
Find Deal
Sat, Nov 8 - Tue, Nov 11
United Airlines Logo
6:00 am - 7:24 amONT-SFO
1h 24mnonstop
United Airlines Logo
9:30 pm - 10:51 pmSFO-ONT
1h 21mnonstop
$99United Airlines
Find Deal
Tue, Oct 28 - Tue, Nov 4
Delta Logo
7:35 am - 12:49 pmONT-PDX
5h 14m1 stop
Delta Logo
5:30 am - 11:08 amPDX-ONT
5h 38m1 stop
$157Delta
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Tue, Oct 21 - Tue, Oct 28
American Airlines Logo
6:10 am - 11:10 amONT-DFW
3h 00mnonstop
American Airlines Logo
9:35 pm - 10:42 pmDFW-ONT
3h 07mnonstop
$159American Airlines
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Sat, Oct 11 - Tue, Oct 14
Delta Logo
11:48 am - 7:19 pmONT-PDX
7h 31m1 stop
Delta Logo
5:00 pm - 11:39 pmPDX-ONT
6h 39m1 stop
$167Delta
Find Deal
Wed, Oct 29 - Sat, Nov 1
American Airlines Logo
11:59 pm - 10:06 amONT-ORD
8h 07m1 stop
American Airlines Logo
6:45 am - 11:57 amORD-ONT
7h 12m1 stop
$183American 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 $58 round-trip. The most popular route is from Ontario (ONT) to Denver (DEN), and the cheapest round-trip airline ticket found on this route in the last 72 hours was $96.

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 $277, 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 $276 (return) on average. On the other hand, the most expensive months are December and March, when the average cost of round-trip tickets is $458 and $382 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 Friday and avoid Wednesdays 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 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, 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 and prices are also 10% lower on average.
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 $356.

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 $130 one-way - $170 round-trip; Dallas $143 one-way - $245 round-trip; Las Vegas $60 one-way - $93 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 4242 reviews
7.0Food
8.0Comfort
8.1Boarding
7.5Entertainment
8.6Crew
Airline reviews

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

10.0 ExcellentRobert, Sep 2025SFO - LAS
Read more Southwest reviews

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!

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.

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.

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.

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

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

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.

While waiting to claim my checked luggage, I discovered the airline had lost it. After a long wait and inquiries, I discovered it was on another flight. Fortunately, the airline finally sent my luggage home.

Was not able to watch most shows on the entertainment site. They would not load

Our flight was 1.5 hours delayed. There was no weather for the inbound flight, so I don't understand why. This meant a VERY late arrival and only a quick nap before my morning flight.

Delayed flight, so I switched fights to SFO to Phoenix , Phoenix to DSM. Excellent service through American Airlines

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!

Seats were new and comfortable. Staff was fine. Missed my connection due to weather -which wasn’t their fault- but got no help at all. Gate staff sent me to customer service, which was and stayed unstaffed. Sign with QR code directed me to call or chat. Chat was useless. Call was returned after an hour. No itinerary offered by Frontier could get me home in less than 30 hours. Rebooked with another airline and got a partial refund that came to about 10 percent of what I paid to get home.

Finally a Frontier on time and efficient. I've had problems before with your airline, but this time everything went fine.

The experience was good. No frills but I got there safe and sound and on time.

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

sluggish boarding and arrival procedures, fake nice flight attendants, and lots of delays.

Disaster. They lied every step of the way. We ended up being delayed due to crew and then allegedly abandoned the flight because of a curfew at LGA. No rebooking to LGA at any reasonable time. No hotel. No meal vouchers. Had to sleep in the airport and fly to Newark instead. Will never fly Frontier again.

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….

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