$28 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 3/31. 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$200
Los Angeles
Los Angeles1 stop$126
Las Vegas
Las Vegasnonstop$58
Chicago
Chicago1 stop$164
Miami
Miami1 stop$172
San Francisco
San Francisco1 stop$125
Boston
Boston1 stop$254
Washington, D.C.
Baltimore1 stop$200
Denver
Denvernonstop$78
Fort Lauderdale
Fort Lauderdale1 stop$200
Seattle
Seattlenonstop$128
Atlanta
Atlanta1 stop$201
Dallas
Dallasnonstop$128
Tampa
Tampa1 stop$194
Houston
Houstonnonstop$137
Honolulu
Honolulunonstop$306
San Diego
San Diego1 stop$126
Philadelphia
Philadelphia1 stop$200
New York
New York1 stop$200
Los Angeles
Los Angeles1 stop$126
Las Vegas
Las Vegasnonstop$58
Chicago
Chicago1 stop$164
Miami
Miami1 stop$172
San Francisco
San Francisco1 stop$125
Boston
Boston1 stop$254
Washington, D.C.
Baltimore1 stop$200
Denver
Denvernonstop$78
Fort Lauderdale
Fort Lauderdale1 stop$200
Seattle
Seattlenonstop$128
Atlanta
Atlanta1 stop$201
Dallas
Dallasnonstop$128
Tampa
Tampa1 stop$194
Houston
Houstonnonstop$137
Honolulu
Honolulunonstop$306
San Diego
San Diego1 stop$126
Philadelphia
Philadelphia1 stop$200

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, Mar 28 - Sat, Apr 4
Frontier Logo
2:23 pm - 3:37 pm
ONT
-
LAS
1h 14mnonstop
Frontier Logo
10:30 am - 11:39 am
LAS
-
ONT
1h 09mnonstop
$58Frontier
Sat, Mar 14 - Mon, Mar 16
Frontier Logo
2:23 pm - 3:37 pm
ONT
-
LAS
1h 14mnonstop
Frontier Logo
7:00 am - 8:06 am
LAS
-
ONT
1h 06mnonstop
$59Frontier
Sat, Mar 14 - Mon, Mar 16
Frontier Logo
2:23 pm - 3:37 pm
ONT
-
LAS
1h 14mnonstop
Frontier Logo
2:28 pm - 3:37 pm
LAS
-
ONT
1h 09mnonstop
$60Frontier
Sat, Apr 25 - Tue, Apr 28
Frontier Logo
7:44 pm - 8:54 pm
ONT
-
LAS
1h 10mnonstop
Frontier Logo
5:41 pm - 6:49 pm
LAS
-
ONT
1h 08mnonstop
$62Frontier
Thu, Apr 16 - Tue, Apr 28
Southwest Logo
3:00 pm - 8:05 pm
ONT
-
SEA
5h 05m
1 stop
Southwest Logo
9:20 am - 3:05 pm
SEA
-
ONT
5h 45m
1 stop
$146Southwest
Mon, Mar 23 - Fri, Mar 27
Delta Logo
5:09 pm - 12:03 am
ONT
-
SEA
6h 54m
1 stop
Delta Logo
7:50 pm - 10:34 pm
SEA
-
ONT
2h 44mnonstop
$147Delta
Fri, Apr 17 - Tue, Apr 21
Delta Logo
12:49 pm - 11:08 pm
ONT
-
HOU
8h 19m
1 stop
Delta Logo
6:00 am - 11:36 am
HOU
-
ONT
7h 36m
1 stop
$237Delta
Wed, Apr 15 - Wed, Apr 29
United Airlines Logo
11:05 am - 11:17 pm
ONT
-
EWR
9h 12m
1 stop
United Airlines Logo
3:40 pm - 8:36 pm
EWR
-
ONT
7h 56m
1 stop
$272United Airlines
Sat, Apr 11 - Tue, Apr 14
American Airlines Logo
2:08 pm - 11:47 pm
ONT
-
HOU
7h 39m
1 stop
American Airlines Logo
6:01 am - 10:09 am
HOU
-
ONT
6h 08m
1 stop
$295American Airlines
Wed, Apr 15 - Wed, Apr 22
Southwest Logo
12:55 pm - 5:55 pm
ONT
-
HOU
3h 00mnonstop
Southwest Logo
9:00 pm - 10:25 pm
HOU
-
ONT
3h 25mnonstop
$317Southwest
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 Las Vegas (LAS), and the cheapest round-trip airline ticket found on this route in the last 72 hours was $58.

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 $342, 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 $272 (return) on average. On the other hand, the most expensive months are March and December, when the average cost of round-trip tickets is $382 and $370 respectively.

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

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

When flying from Ontario to United States, you should consider leaving on a Sunday and avoid 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 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 23% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 4 weeks before departure.

Good to know

Low seasonJanuary
Cheapest flight$28
Best time to beat the crowds but there is an average 1% increase in price.
Most popular time to fly with an average 1% 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 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.

  • 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 at night, when round-trip flights cost $358 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 $123 one-way - $194 round-trip; Dallas $138 one-way - $294 round-trip; Las Vegas $69 one-way - $101 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 4298 reviews
8.0Comfort
8.6Crew
7.5Entertainment
7.0Food
8.1Boarding
Airline reviews

The charges were ridiculous for an hour flight and the turbulence was very scary.

2.0 MediocreDarcey, Feb 2026
SAN - SJC
Read more Southwest reviews

The charges were ridiculous for an hour flight and the turbulence was very scary.

The seats are now more narrow. I paid for front row the seats in the front are even more narrow than before.

The wifi on the plane is great. The only issue that I have is that I prefer an aisle seat and on my trips this week, I was either in the middle or window. If we can work to secure aisle seating, I will be thrilled. Nice trip.

Great flight but super high price. Glad it was a business trip and not personal

3 hour delay. Had to change plans and was still delayed.

We got exit row seats both flights. Everything was running on time

The boarding and seat assignment system no longer works for me, but I know it is being replaced. Otherwise, I am good with the overall experience.

The lead steward kept singing about "San Francisco" and hotel California---more annoying than humorous....needs work. Flight was smooth and on time.

San Diego airport is brand new, spacious, airy and very smooth checkin at SW baggage drop.

Crew could have been friendlier, maybe I'm spoiled by SW crews. In flight wifi was good. Would be nice to have more food offerings on a 4 plus hour flight

Flight was delayed by 3-hours and their fix was… complimentary pretzels.

The crew, and fellow passengers, were super gracious and kind. There seemed to be plenty of bin space even though the plane was full. It’s nice to get a glass of wine with dinner in Premiere seating, and there was a lot of food.

Everything I mentioned earlier - the airbus was more comfortable indeed and the experience was further enhanced.

The plane was an older model, so it wasn’t as comfortable as others. The flight attendants were not helpful during onboarding. It was a full flight so there was chaos finding space for baggage.

Awesome! On time flight, early arrival, and a complimentary upgrade!

Delta One is extraordinary. I fly business when somebody hires me. I just wonder why there is such a chasm between business class and the insanely inhumane and nonsensical coach. The seats are not large enough to fit even my tiny wife. We fly 10% of what we did because we don’t want to pay 5-10 k but for $400 it’s unbearable. It seems like the accountants took over and made stupid decisions. Screw in 20 extra seats and make it so unbearable that people fly 90% less. Just put the damn price up and put some proper chairs in. But business, yay.

Delta’s staff is unmatched. From the gate agents, to the pilots, to the flight attendants… all top of the industry.

The flight was delayed for about 2 hrs. Other than it, it was good.

I am extremely disappointed that delta internal pilot manuals now refer to the Gulf of Mexico as the “gulf of America”. You can bow down to the Orange turd on your own. I will never fly delta again

No lunch on a x-country flight scheduled for 10:50 am departure, arrived 5+ hrs later. That requires a black box label before you pay for the tickets. Worst, when I checked in online, it's specifically said that lunch was served on his flight for economy Plus passengers.

Women boarding passengers at the gate was absolutely rude and disrespectful of passengers. The flight attendant was absolutely delightful! Smiling and connected with the passengers. So happy. The seats are cramped and uncomfortable but I guess that’s just the way it is Communication regarding flight was excellent

it was a very short flight so my expectations were low.

Very disappointing given gate agent behavior. Filed a formal complaint with United.

Crew was great (professional, attentive, prompt). Snacks for 4 hrs flight is deplorable.

Flight delayed. WiFi connectivity very poor if not existant. Last minute arrival forced me to run to catch my connection.

Terrible. No customer service, no food, no drinks on a 6 hour premier economy booking.

It was a pretty standard flight... until the almost hour and a half spent on the taxi way. I get that the weather has been poor but the delay had nothing to do with the weather and more to do with a plane with several issues tying up the gate. I get that that happens from time to time but this has been EVERY flight I've been on for the past 5 years and I fly 3 to 5 times a year. This isn't just United... it's American, it's Delta. It's an issue with the entire industry. I work for UPS and packages on a cargo plane get better service than people do these days. Anymore I HATE flying.

The flight crew where really good. Better then the crew from BNE to SFO

left on time, reasonable boarding process arrived early luggage came out quickly

I’m so sorry, I can’t remember her name, I believe it was Dimpti. She was stellar, also a mature Asian flight attendant, lots of flowers in her hair, just as amazing! But literally the crew was AWESOME . Only downside is there weren’t any charging outlets. Maybe I needed to ask a flight attendant , but it would’ve been nice to have one easily accessible.

Experience was great. The best part is the free Wi-Fi connection which helps me to work on the flight

The flight was fine. It's the satellite terminal that supports American eagle flights is what sucks. There is only one food option and everything there is way overpriced. I mean I know it's airport pricing, but it's even crazier than that. I bought a sandwich in a plastic container for $18.

The flight was really crowded. Flight attendants were just ok.

Flight was delayed for 2 hours, then last minute the change to on time. The satélite location is far and a nightmare to get to.

We flew in first class. The crew did not offer drinks before the flight took off, but they treated us well during the flight. The food was excellent. There was actually too much food served, but it was nice to have all the options.

For a 5 1/2 hour flite i considered the "business class" to be subpar. The seats were just ok, no amenities, really nothing more than a long domestic flight. Frankly disappointed.

It would be nice to have some low carb options in the snacks.

The entertainment options were at best, fair. It was exactly the same as my outbound flight. It would have been more entertaining if there were some series from Apple TV, HBO, Showtime or other carriers for me to catch up with.

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

Overall experience was great. Flights were almost on time in departing and we arrived at our destination as scheduled. No issues with amenities or flight crew. Everything went well as as expected. Will fly again with American Airlines in the future!

Gate not determined until I got to the airport - hard to plan the trip to the airport.

Our flight was canceled. I will never use Kayak nor Frontier for travel again. The entire experience was a headache.

Frontier.. nickel and dime add-ons. Flight late, on time, late again, last minute gate change, arrival gate required a shuttle to the terminal. They sure keep you guessing.. if you like a little chaos and airport anxiety, this is the airline for you!

This is my second time flying with Frontier. My current experience was very favorable. The staff from the gate to the plane was friendly, warm and professional. The food options lacked in my opinion. This area needs some attention in my opinion.

There was no food and no entertainment, so I'm not sure why these are even in the survey, as my understanding is frontier does not ever offer food without a few, not even a snack, and there are no screens so unless the flight safety talk is our entertainment why ask how we liked it?. One of the flight attendants say in the back of the plane as people filed in to their seats, yelling orders about where to put baggage and telling people to hurry up. It was the least professional experience I've ever had on a flight.

Very well recently! Frontier is improving and less harrassing customer on luggages! Positive!

Good for a budget airline! It was easy to get on, staff was really nice. Can’t say anything about the food or entertainment because it wasn’t available, which is fine.

I am writing to express my disappointment with my recent Frontier Airlines flight. I was charged $99 at the gate because my bag was said to be too large, yet once onboard there was no available overhead bin space, and I was required to place the bag under the seat in front of me anyway. This made the charge feel unnecessary and unfair. Additionally, before the flight even took off, I was asked to move from the seat I paid for into a middle seat so another passenger and her cat could have my seat to themselves. I was not offered compensation or an explanation for being moved from a paid seat. Between the unexpected bag fee and being forced to give up my seat, this experience fell well below acceptable customer service standards. I would appreciate a review of this situation and appropriate compensation.

It was ok. It was expensive to check 2 bags ($75.00 per bag), and then it took a long time to wait for shuttle to take us from one terminal to the terminal where the plane was taking off at LAX. And all of this for a flight where we had to pay for any food or drink that was not water.

When I wanted to check in 3 hours prior to boarding time, the employees mentioned “a little over an hour delay” so I waited for an hour then I went to go look for food in the terminal and most people from that flight were in the same area looking for food. Finally I decided after food to check to see if it’s anytime closer and now it’s 2 mins until boarding closes?! What are you kidding me? I didn’t receive anything via sms about boarding now nor via email or on the intercom. I luckily made it through, barely, and then there’s no room for my carry on mind you I’m in the very first row so I had to place my purse in one further row back and my carry on sections down. Not sure who pays for better seats to get your stuff placed all over the plane but that was the worst experience I’ve ever had flying with anyone.

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

Information on your arrival and departure airports