$28 Find Cheap Flights from Ontario to the United States - Compare and Save

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Ontario to the United States departing on 8/24. 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.
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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$293
Los Angeles
Los Angeles1 stop$128
Las Vegas
Las Vegas1 stop$119
Chicago
Chicago2 stops$276
San Francisco
San Franciscononstop$72
Miami
Miami1 stop$205
Boston
Boston1 stop$332
Fort Lauderdale
Fort Lauderdale1 stop$238
Washington, D.C.
Baltimore2 stops$238
Denver
Denvernonstop$105
Seattle
Seattle1 stop$219
Atlanta
Atlanta2 stops$333
Dallas
Dallasnonstop$250
Tampa
Tampa1 stop$242
Houston
Houstonnonstop$162
San Diego
San Diego1 stop$151
Honolulu
Honolulu1 stop$375
Philadelphia
Philadelphia2 stops$238
New York
New York1 stop$293
Los Angeles
Los Angeles1 stop$128
Las Vegas
Las Vegas1 stop$119
Chicago
Chicago2 stops$276
San Francisco
San Franciscononstop$72
Miami
Miami1 stop$205
Boston
Boston1 stop$332
Fort Lauderdale
Fort Lauderdale1 stop$238
Washington, D.C.
Baltimore2 stops$238
Denver
Denvernonstop$105
Seattle
Seattle1 stop$219
Atlanta
Atlanta2 stops$333
Dallas
Dallasnonstop$250
Tampa
Tampa1 stop$242
Houston
Houstonnonstop$162
San Diego
San Diego1 stop$151
Honolulu
Honolulu1 stop$375
Philadelphia
Philadelphia2 stops$238

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, Aug 15 - Mon, Aug 17
Frontier Logo
8:58 am - 10:25 am
ONT
-
SFO
1h 27mnonstop
Frontier Logo
9:33 am - 11:02 am
SFO
-
ONT
1h 29mnonstop
$72Frontier
Tue, Aug 25 - Sat, Aug 29
Frontier Logo
3:13 pm - 4:40 pm
ONT
-
SFO
1h 27mnonstop
Frontier Logo
9:33 am - 11:02 am
SFO
-
ONT
1h 29mnonstop
$73Frontier
Sat, Aug 15 - Wed, Aug 19
Frontier Logo
8:58 am - 10:25 am
ONT
-
SFO
1h 27mnonstop
Frontier Logo
12:33 pm - 2:03 pm
SFO
-
ONT
1h 30mnonstop
$74Frontier
Sat, Aug 22 - Wed, Aug 26
American Airlines Logo
10:29 am - 3:39 pm
ONT
-
DFW
3h 10mnonstop
American Airlines Logo
5:47 pm - 6:47 pm
DFW
-
ONT
3h 00mnonstop
$255American Airlines
Tue, Sep 8 - Tue, Sep 15
American Airlines Logo
12:59 pm - 11:58 pm
ONT
-
JFK
7h 59m
1 stop
American Airlines Logo
7:15 am - 12:06 pm
JFK
-
ONT
7h 51m
1 stop
$296American Airlines
Fri, Aug 21 - Fri, Aug 28
Southwest Logo
7:00 am - 10:15 pm
ONT
-
LGA
12h 15m
1 stop
Southwest Logo
6:10 am - 1:25 pm
LGA
-
ONT
10h 15m
2 stops
$298Southwest
Tue, Aug 25 - Thu, Sep 3
Southwest Logo
5:45 am - 4:55 pm
ONT
-
LGA
8h 10m
2 stops
Southwest Logo
10:20 am - 10:05 pm
LGA
-
ONT
14h 45m
2 stops
$303Southwest
Mon, Aug 31 - Fri, Sep 4
United Airlines Logo
7:13 pm - 9:13 am
ONT
-
LGA
11h 00m
2 stops
United Airlines Logo
5:25 pm - 10:35 pm
LGA
-
ONT
8h 10m
1 stop
$304United Airlines
Mon, Aug 17 - Tue, Aug 25
United Airlines Logo
1:56 pm - 7:28 pm
ONT
-
HNL
8h 32m
1 stop
United Airlines Logo
9:40 pm - 12:12 pm
HNL
-
ONT
11h 32m
2 stops
$375United Airlines
Tue, Aug 18 - Thu, Aug 27
Alaska Airlines Logo
12:04 pm - 7:16 pm
ONT
-
HNL
10h 12m
1 stop
Alaska Airlines Logo
1:33 pm - 10:10 pm
HNL
-
ONT
5h 37mnonstop
$379Alaska 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 5 days was to San Francisco, at $60 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 5 days was $220.

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 $432 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 $432.

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 $376, 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 September, when tickets cost $294 (return) on average. On the other hand, the most expensive months are June and July, when the average cost of round-trip tickets is $424 and $412 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 Saturdays 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 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 3 weeks before departure, which saves you about 30% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 4 weeks before departure.

Good to know

Low season

January

Cheapest flight

$28
Best time to beat the crowds with an average 5% drop in price.
Most popular time to fly and prices are also 10% lower on average.
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 
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 $186 one-way - $287 round-trip; Dallas $186 one-way - $350 round-trip; Seattle $193 one-way - $277 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 4231 reviews
8.0Comfort
8.1Boarding
7.5Entertainment
7.0Food
8.6Crew
Airline reviews

Red eye from San Diego. Temperature of the cabin was way too warm and the air duct flowed very little air.

6.0 GoodGordon, Jul 2026
SAN - MCO
Read more Southwest reviews

Red eye from San Diego. Temperature of the cabin was way too warm and the air duct flowed very little air.

I think Southwest is the number one airline that anyone can fly I have flown for the first time Frontier and what a joke and their customer service United was a very strange experience I'm only sticking to Southwest from here on out for sure

Great job Southwest! My family doesn't fly often but we felt safe the whole time.

Flight was delayed, full flight and I had to change gates. Southwest flights are always late later in the day.

Was fine, delayed and feels like southwest is always late

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!

I liked receiving attention from aged and well experienced flight attendants. I disliked the non-gluten-free snack but I brought my own so I was OK.

The seat on row 11 was a little hard cause my butt was hurting a little bit from sitting after and hour.

The first flight was fine, great crew, but the plane was delayed 45 minutes to go to Seattle because of they were missing a ramp. That would make sense if the plane was actually at the gate. Not if we’re still waiting for a plane. After we landed we waited 30-45 minutes on the tarmac just to get off the plane. Alaska made me miss my connecting flight, wasting my time, and my money. I should honestly be reimbursed, but hey, when does the airline ever actually take accountability? Never.

Wish there were more complimentary drinks available - only had water and apple juice. Also - no snacks were provided during the flight, but we were offered some items as we exited the plane.

My daughter has anxiety and became nauseous after boarding the plane and before take off. She went to the plane bathroom and ended up having to vomit, and your staff promptly removed us from the flight. We explained that it was due to my daughter’s anxiety, and that the condition would not continue in the air, but they removed us anyway. We have flown many many times before on many different airlines and my daughter’s anxiety has resulted in nausea and sickness before takeoff, and every airline has been accommodating and professional. This is was our first time flying with your airline, and also the first time we have ever been removed from a flight. This was the worst service we have ever experienced. This was a special surprise trip we gifted to my daughter for graduating college. I had also paid to upgrade the family to first class and sit all together which we had never done before and can’t afford on a normal basis. Our removal from the flight was not only extremely embarrassing, but devastating for my daughter. My daughter and I were removed from the plane and a call was made by your staff to medical personnel, a few questions were asked of my daughter, and then she was magically cleared. All of this took mere minutes. Why this could not have been performed while we were on the plane, or why this could not have been performed off the plane and then us allowed to reboard is beyond me. My wife and youngest daughter continued on the original flight alone and were very upset and crying due to the situation, yet the staff did nothing to console or assist them. My wife states that upon arrival in Portland and as they were exiting the plane, one of the stewardesses involved said “byyyyeeeee” to them sarcastically and laughed. Myself and my oldest daughter had to wait 4 hours for an alternate flight and were sat in regular seats because our first class seat purchase could not be honored. My wife wasn’t allowed to pick up our rental car and had to wait 4 hours with our luggage until I arrived. The delay prevented us from being able to carry out planned events and ruined the first day of our trip. Upon explaining all of this to your customer service, we received no sympathy, assistance, or compensation other than your staff submitting a request for a reimbursement of my and my daughters first class upgrade cost. When checking in early for our flight back home, the luggage cost for myself and my eldest daughter was no longer discounted as it was for my wife and youngest daughter. Customer service once again could not assist me over the phone and rectify what should have been a minor adjustment. Instead they stated I would have to wait until we physically checked bags in at the airport and then ask staff to adjust the luggage cost. With everything else we had experienced, I was not going to leave that to chance and instead paid full price for the luggage ahead of time. Or experience with Alaska Airlines was a complete disaster and I am baffled at the lack of empathy and assistance from your staff. I’m not sure of what else to say other than the fact that unless we are compensated by Alaska Airlines in some form to offset the horrendous service we received, we will be relaying our experience to family and friends and on social media, and doing all we can to urge everyone to avoid utilizing your services.

I got an email 3 hours before the flight letting me know it got canceled

Boarding was easy and quick. Staff was very friendly. Service of snacks and drinks by staff was outstanding.

It was ok! Not fond of sitting in middle seat. Tried to upgrade with my Atmos card but it was a new account and they weren’t able to look up my account details.

Not bad. Due to not buying a seat, on the way back, my seat was not assigned till 2 hrs before the flight left. Got me worried I wouldn’t have a seat.

There is no entertainment on the plane. The snack is minimal. The crew was nice and professional.

The first leg of the trip was excellent. Lovely flight attendants and comfortable plane. The second leg left a lot to be desired. The flight attendant was rude when I asked for a Diet Coke, the boarding required quite a long walk and the plane was crammed and uncomfortable.

Flight was late, the only reason I almost missed my flight was that my connection was also late.

Baggage claim signs were not updated with my flight information, so I had to guess. The app wasn't updated either.

It was a short, comfortable flight. It did leave an hour late due to the pilot having to be replaced (family emergency) but that didn’t inconvenience myself & my friend. The situation was explained, eventually.

UA594 was delayed multiple times. I ended up getting picked up so I can make it in time for work 6AM on Monday, 7/6/2026

Boarded from a very small gate at LAX. Staff at gate had us line up, then waited 25 minutes to board without a word of explanation. Plane arrived on time then waited 20 minutes for a plane to vacate our gate. Majority of bags arrived after 15 minutes but it took an hour for a small number of remaining bags to be off-loaded despite my “priority” bag tag.

Great staff. Clean plane, but we were delayed for more than an hour due to maintenance issues and had to board another plane.

Lost one piece of luggage even though I checked in 2.5 hours before the flight

The boarding process on the departure from LA was rather slow even though I was in Group 1. For first class, I was not expecting to have to pay for Wi-fi but I did and then the wi-fi was spotty. The entree was surprisingly good and so that was a pleasant surprise. However, once I got to Houston, it was terrible. Unfortunately there was bad weather but the constant gate changes for my connecting flight was difficult to manage due to having to navigate back and forth between different terminals.

Service was professional and quick. Premium economy seat was comfortable given the class

Seat pitch is horrible especially on the 15 hour flight. Gate crew at SFO was Outstanding. The flight crew was also great.

My seat had a worn out cushion, which made it a bit uncomfortable. Other than that, the flight was excellent.

American was the airline that Starlux contracted for this trip. I arrived in time to make the connecting flight on American, and then the baggage-handler debacle happened. For some reason, the first class and premium economy passengers' luggage was unloaded first. Never seen this happen before. They had handlers removing the bags from the carousel for those passengers. Meanwhile, all of the economy passengers were waiting for their bags, including me. And there were a lot of bags because it was an international flight packed full. While waiting for 45 minutes, my bag didn't show. Meanwhile, an American representative showed up asking if anyone has a connecting flight to Phoenix. Of course I spoke up, and they proceeded to try to find my bag because I had to take a bus to the actual terminal to catch my flight. Which I was not informed of before I arrived. After another 15 minutes of searching, my bag was finally found with the first-class passengers' bags because they had pulled it by mistake. So I rushed to the terminal with the American representative to catch my flight, and they informed me that I missed it and could not get another flight until the next day. Of course, after being on an international flight for 18 hours, I was in no mood to hear this. Now, to be fair, there were a few American employees who tried to help me. After hearing about the missed flight, they got a supervisor to talk to. I expressed my situation to the supervisor, and she was not helpful until I asked for compensation. She agreed to get me a hotel room for the night. So I agreed, and she disappeared into her office, and I waited. And waited. And waited. And waited. While waiting, I was asked by three different employees who knew of my situation if I had been helped. I told them I was waiting for the supervisor to get the hotel room, and they said they would check. Finally, after waiting for 75 minutes, one of the employees who had asked me if I had been helped arrived with my hotel room and arranged a ride to the hotel for me. Never saw the supervisor again. It was now 8 o'clock; I arrived at 5:45! My rebooked fight was scheduled for 6:11 this morning and I have now been informed it has been delayed until 10:00. So am I happy with American? NO I'M NOT!! ;

Not good. Flight crew, was not friendly and just shoved stuff at us. Not the way I like to travel.

The WiFi didn’t work entire flight, couldn’t watch a movie. The recline button didn’t work

Ontario airport boarding was very easy to park and access, is clean and TSA took 10 minutes total. Check-in was a breeze and cruise was very nice.

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

The flight was on time and arrived early. The crew were friendly and helpful.

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!

VERY disappointed at the agent checking in my luggage. I know that the weight limit is 23 kg, a little over 50 pounds (50.71 pounds). Yet the agent kept repeating "50 pounds". So I said, the limit is 23 kg, and she had the audacity to say 'no, it is 22 kg!" Imagine my surprise. Was she ignorant or was she poorly trained? Not sure. The boarding process was pretty good. The speakers were loud enough so I still could hear them despite inconsiderate passengers continuing to speak while the announcements were going on. During the flight, the teenage girl sitting behind me kept pressing her feet to the back of my chair. I turned around several times, yet she did not get the hint. I did not make a fuss since I sense I had a bad streak that night with AA, so I just did the best I can to lean forward and not let that bother me.

It was wonderful upgrading to first. Plane was so cold thou. Crew was great. Wish there was a food option in first for such a long flight. Doesnt matter the time of day. Chintzy.

The seats are tiny and they don’t recline. The planes are dirty and very small. You have to pay for carry on and even the personal item that you’re allowed is smaller than with other airlines. Flights are usually delayed and there’s no screens or any amenities or entertainment.

The takeoff was the smoothest I've ever experienced on any airline and this is the first time I've flown on frontier so this was an extremely pleasant surprise!

A lady asked to stop the flight after the tunnel pulled away and we began to depart a flight that was already hours late. The attendance respectfully stopped the the plane and had the tunnel return. After the tunnel returned the passenger claimed to have changed her mind . The tunnel was then put in reverse and the passenger remained on the plane .. They should have sent the sick passenger off the plane like initially replaced. They existed a couple off the plane prior to that situation.. So.. all and all.. it was a long and flight.. .

We understand and comply with Frontier’s bag sizes. We’ve had some problems in past while having to await other passengers who do not understand the baggage restrictions or have not prepaid and that is usually our biggest concern (others delaying us) with flying Frontier. Flying OUT of ONT, however, has always been a great experience. I’ve also noted even on delayed Frontier flights very knowledgeable pilots who manage expectations well.

Long lines, rude staff, everything that's offered you have to pay for.

The last time I flew Frontier was in the 1960s when it was a “real” airline. We flew this time because of the price & schedule. As the saying goes, you get what you pay for.

I appreciated the upgrade to free cary-on bag and seat selection at no charge

Flight was delayed on the runway for 40 minutes the crew did not even offer even water to passengers to compensate for the flight delayed. The flight was delayed due to aircraft mechanical issues. Worst customer service ever

This isna terribly run airlines. If you're one minute late, they will deny your ticket. Don't waste your time or money

Flight was delayed for more than 3 hours, crew at ONT airport was rude, and when we got to DFW the airplane had an issue landing, we had to be taxied to the terminal, and the luggage was hold until the next day.

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

Information on your arrival and departure airports