WAS - ONT

$90 Find Cheap Flights from Washington, D.C. to Ontario

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Washington, D.C. to Ontario departing on 9/10. 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

KAYAK searches hundreds of travel sites at once for deals on flights to Ontario

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Washington, D.C. to Ontario, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Washington, D.C. to Ontario, as well as popular online travel agencies
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Cheap Flights from Washington, D.C. to Ontario (WAS-ONT)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Washington, D.C. to Ontario 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 Washington, D.C. to Ontario

Thu, Sep 11 - Thu, Sep 18
Frontier Logo
10:17 am - 3:29 pmIAD-ONT
8h 12m1 stop
Frontier Logo
4:14 pm - 9:17 amONT-IAD
14h 03m1 stop
$161Frontier
Find Deal
Thu, Sep 11 - Sun, Sep 14
Frontier Logo
10:17 am - 3:29 pmIAD-ONT
8h 12m1 stop
Frontier Logo
7:15 pm - 9:17 amONT-IAD
11h 02m1 stop
$162Frontier
Find Deal
Wed, Nov 12 - Tue, Nov 18
United Airlines Logo
4:10 pm - 10:51 pmIAD-ONT
9h 41m1 stop
United Airlines Logo
1:33 pm - 11:15 pmONT-IAD
6h 42m1 stop
$292United Airlines
Find Deal
Tue, Nov 11 - Sat, Nov 15
Delta Logo
7:15 am - 12:18 pmBWI-ONT
8h 03m1 stop
Delta Logo
7:05 am - 5:22 pmONT-BWI
7h 17m1 stop
$297Delta
Find Deal
Wed, Oct 15 - Wed, Oct 22
Delta Logo
7:35 am - 5:10 pmIAD-ONT
12h 35m1 stop
Delta Logo
11:48 am - 12:40 amONT-IAD
9h 52m1 stop
$297Delta
Find Deal
Tue, Nov 11 - Sat, Nov 15
United Airlines Logo
4:10 pm - 10:51 pmIAD-ONT
9h 41m1 stop
United Airlines Logo
7:00 am - 5:30 pmONT-IAD
7h 30m1 stop
$302United Airlines
Find Deal
Fri, Oct 3 - Sat, Oct 11
American Airlines Logo
2:21 pm - 9:24 pmIAD-ONT
10h 03m1 stop
American Airlines Logo
10:09 am - 11:53 pmONT-IAD
10h 44m2 stops
$332American Airlines
Find Deal
Fri, Oct 3 - Sat, Oct 11
American Airlines Logo
2:21 pm - 9:24 pmIAD-ONT
10h 03m1 stop
American Airlines Logo
10:09 am - 11:53 pmONT-IAD
10h 44m2 stops
$334American Airlines
Find Deal
Tue, Nov 11 - Sun, Nov 16
Southwest Logo
4:40 pm - 8:55 pmIAD-ONT
7h 15m1 stop
Southwest Logo
2:15 pm - 11:30 pmONT-IAD
6h 15m1 stop
$338Southwest
Find Deal
Fri, Nov 14 - Wed, Nov 19
Southwest Logo
5:05 am - 9:10 amIAD-ONT
7h 05m1 stop
Southwest Logo
8:30 am - 10:10 pmONT-IAD
10h 40m2 stops
$351Southwest
Find Deal
Booking Insights

KAYAK's insights & trends for Washington, D.C. to Ontario flights

Get data-powered insights and trends into flights from Washington, D.C. to Ontario to help you find the cheapest flights, the best time to fly and much more.

What is the cheapest Washington, D.C. to Ontario flight route?

Data is based on round-trip flight searches on KAYAK over the past month.

The cheapest return flight from Washington, D.C. to Ontario costs $282 on the route between Baltimore (BWI) and Ontario (ONT). It is also the most popular route.

What’s the cheapest day of the week to fly from Washington, D.C. to Ontario?

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

If you are looking for a flight deal from Washington, D.C. to Ontario, look for departures on Thursdays and avoid leaving on a Saturday, as it's usually the priciest day. When flying back from Ontario, Thursday is the cheapest day to fly and Monday is the most expensive.

What is the cheapest month to fly from Washington, D.C. to Ontario?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Washington, D.C. to Ontario, 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 Washington, D.C. to Ontario is April, where tickets cost $326 (return) on average. On the other hand, the most expensive months are November and December, where the average cost of round-trip tickets is $456 and $430 respectively.

Can I save money by flying with a layover from Washington, D.C. to Ontario?

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 $379, prices are generally cheapest when you fly direct.

How far in advance should I book a flight from Washington, D.C. to Ontario?

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Washington, D.C. to Ontario, 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 Washington, D.C. to Ontario, you should book around 3 weeks before departure, which saves you about 46% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 9 weeks before departure.

Good to know

Low seasonSeptember
Cheapest flight$90
Best time to beat the crowds but there is an average 3% increase in price.
Most popular time to fly with an average 12% increase in price.
Flight from Reagan Washington National Airport to Ontario

When to book flights from Washington, D.C. to Ontario

Are your dates flexible? Find out the best times to travel from Washington, D.C. to Ontario based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking flights from Washington, D.C. to Ontario

  • What is the cheapest flight from Washington, D.C. to Ontario?

    In the last 3 days, the lowest price for a flight from Washington, D.C. to Ontario was $90 for a one-way ticket and $161 for a round-trip.

  • Do I need a passport to fly between Washington, D.C. and Ontario?

    A passport is not required to fly from Washington, D.C. to Ontario.

  • Which airports will I be using when flying from Washington, D.C. to Ontario?

    Washington, D.C. is served by 2 major airports and there is only 1 main airport in Ontario. You will leave Washington, D.C. from one of these airports: Washington, D.C. Reagan-National or Washington, D.C. Dulles Intl. You will be arriving at Ontario.

  • Which airlines offer Wi-Fi service onboard planes from Washington, D.C. to Ontario?

    Hawaiian Airlines, and Alaska Airlines offer inflight Wi-Fi service on the Washington, D.C. to Ontario flight route.

  • Which aircraft models fly most regularly from Washington, D.C. to Ontario?

    The Boeing 737-800 Passenger/BBJ2 (winglets) is the aircraft model that flies most regularly on the Washington, D.C. to Ontario flight route.

  • On which days can I fly direct from Washington, D.C. to Ontario?

    There are nonstop flights from Washington, D.C. to Ontario on a daily basis.

  • Which is the best airline for flights from Washington, D.C. to Ontario, Southwest or Delta?

    The two airlines most popular with KAYAK users for flights from Washington, D.C. to Ontario are Southwest and Delta. With an average price for the route of $492 and an overall rating of 8.0, Southwest is the most popular choice. Delta is also a great choice for the route, with an average price of $438 and an overall rating of 7.9.

  • How does KAYAK find such low prices on flights from Washington, D.C. to Ontario?

    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 Washington, D.C. to Ontario.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Washington, D.C. to Ontario?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Ontario from Washington, D.C. 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 Washington, D.C. to Ontario?

    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 to Ontario with an airline and back to Washington, D.C. with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Washington, D.C. to Ontario?

    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 to Ontario from Washington, D.C. up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

KAYAK’s top tips for finding a cheap flight from Washington, D.C. to Ontario

  • Looking for a cheap flight? 25% of our users found flights on this route for $168 or less one-way and $337 or less round-trip.

Reviews of the top 5 airlines serving from Washington, D.C. to Ontario

 
See real verified KAYAK customer reviews for airlines flying from Washington, D.C. to Ontario. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Washington, D.C. to Ontario? 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
8.0Comfort
8.1Boarding
8.6Crew
7.0Food
7.5Entertainment
Airline reviews

Very smooth checking in our luggage with a super pleasant SW agent. I enjoyed a fun entertaining movie.

10.0 ExcellentGordon, Jul 2025GEG - OAK
Read more Southwest reviews

Very smooth checking in our luggage with a super pleasant SW agent. I enjoyed a fun entertaining movie.

First time traveling on Southwest since bag fees were implemented. Usual good service. Just more expensive now.

It was a perfect flight in all aspects! Both legs!

Boarding process, crew were good. But the seats were so uncomfortable that was all I could focus on. I literally had to sit forward so that all 3 of us could fit in row. I will try to avoid Southwest in the future for any flights over 60 minutes.

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

Great experience flying Southwest. The crew was really kind and helpful, and very friendly with our toddler.

Plane late from DC to Austin 30 minutes. Crew made up much of the time enroute to San Diego.

Fine, but how to board on SW versus othrr airlines, is just lame. Goood staff though and all was solid otherwise.

Was as expected. Crowed planes. Too many carryons delaying takeoff. But the ride only took an hour and saved me a lot of time SFO is a not a great airport.

I will be flying again Southwest Airlines. Friendly crew, comfortable and affordable.

I was uncomfortably cold on the plane. Other than that it was uneventful and therefore as enjoyable as a plane ride can be.

Food was surprisingly good but the WiFi was not great

My flight was extremely cold. I had a jacket and a cover was left in each seat. The cover was extremely thin and I have a disability, fibromyalgia and arthrithis and AC air is the worst. I closed my vent and my husbands vent and it still was frigid. I asked the attendant if I could get another cover and she quickly almost dismissively and totally unconcerned stating, (I quote) (one per chair) and walked off so quickly that I didn't get a chance to explain to her that I literally have adisability. I didnt want to make a seen so I set on that flight for over 5 hours in pain, joints locking up and extremely uncomfortable. When my fibromyalgia flares up my joints not only ache but they will lock up also and it takes me days to get back to my regular self even though I take medication for it. I felt like it would not have hurt anyone at all for her to just give me an extra cover because I'm sure they have all types of medical issues in people that fly every day.

Not a "Delta" issue, but a JFK issue: We booked a connecting flight with 3 1/2 hours between to clearn immigration and customs. Our inbound flight (BCN to JFK) was on the taxiway 45 minutes which ate into our layover time. Immigtration was insanely quick with the CBP MPC app; however, clearing TSA (again, after we were ALREADY cleared in Spain on the inbound international flight) took over 95 minutes. This left us with 10 minutes before boarding the connecting flight (JFK to SAN) to walk to the far end of Terminal 4 and try to find food. We didn't find any food that could promise to serve us in under 10 minutes so we boarded the Delta flight after coming off a plance and an 8-hour flight knowing that we wouldn't be served any food on the next 5 1/2 hour flight. I feel like Delta needs to put pressure on the JFK TSA to open more screening stations (by our count, we saw only 5 scanners open and a line of - as we said - over 90 minutes. The insult is that we WERE ALREADY SCREENED through TSA, but as you come off one flight into the USA, you have to go through the whole process again. It seems like if you have a connecting flight, there should be a way to pass through immigration and customs without needing to return through TSA.

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

5 hours of delay that could've been much shorter if Delta had taken the 1 hour delay they imposed on the flight before boarding to run any of the plane checks required for flight to find the hydraulic issue that required nearly 3 hours to fix. $24 of meal credit buys a sandwich and a soft drink. Poor communication within the terminal about what gate we'd be re-boarding from and when we'd be re-boarding.

The entertainment and wifi mostly didn't work on this flight.

Terrible entertainment system - kept freezing and audio kept cutting out. Snacks were mediocre at best for a 5 hour flight.

I am still upset that my bag was lost on a recent trip to Rome ; we were inconvenienced and out €150 Euros ; delta has refused to reimburse us

This had nothing to do with Delta… The flights were on time and flawless. The service was excellent. We purchased seats in (aisle/middle) comfort plus since this was a cross country flight. Unfortunately, the woman seated at the window was 300+ pounds and, as might be expected, covered up about a third of the middle seat also. there was absolutely nothing that Delta could have done about that… I just don’t know what the answer should be. If you purchase a seat, you should should be able to use the entire seat and not just the portion that someone else is not sitting/oozing in. Disappointing…there should be something that could be done….I'm just not sure what solution could be.

Very small cramped plane for an international flight. Everything else was good, but it was maybe the smallest comfort-wise I've ever been on for longer than 3-4 hours and the trip was 7.5

The flight was comfortable with the exit row and great service

Flight was delayed 3 hours. No food and drink vouchers was provided. They offered a mini pretzel bag and water .

Staff was rude. Didn’t give water for 2 hours. Worst service

Was on time until within 1 hour of flight-how does that happen? Staff very friendly.

I liked the choice of lemon ginger tea. I think stewardesses can be more considerate of older people needs.

We were given vouchers we couldn’t use with a 5.5 hour delay

I fly UAL 7-8 times per year. This flight was not up to snuff because it boarded very late "due to unexpected delays in restocking the plane" and yet Flight Aware showed the plane had landed some 10 hours earlier--so I think they could have planned accordingly. The FA's were nice but harried. The video system had to be rebooted 3-4 times. The food service was rather abrupt; they forgot my row and when I asked for my meal, they brought it with some impatience. Overall, the flight was fine, but the little details made it feel somewhat mundane and hurried.

I didn’t get on plane. Passport being processed by consulate with visa application. Tried to cancel through underpricer after purchasing cacelling for any reason. No dice, they are thieves.

When I booked it on Kayak it aaid that I wasn't allowed hamd luggage. I called United Airlines and it took them 6 minutes to figure out if I was allowed free hand luggage. Surely something that simple they should be able to tell me instantly.

My flight was delayed for several hours. Sitting at gate 16 for several hours, I got a text from Kayak the gate changed to 9 before it was announced. Very bad communication at each gate from American Airlines employees. I received 10 notifications of delay from Kayak. My vacation started off horrible! I will write to American Airlines corporate office also.

The AA staff person who checked our bags was curt and almost rude. The FA also seemed unhappy doing her job. Overall it was like riding the school bus back in grade school.

Delayed flight that lead to a missed connection and a 5-hour trip became a 12-hour flight 🙄

There is no room, no gluten free options, or any free internet/entertainment. You have to bring your own tablet or smartphone because there are no screens.

Amazing food, great staff, with one noticable detail missing ...but no seat entertainment in any of aircraft ...I am not a fan

Boarding gate in Honolulu was staffed with a great clerk with a soothing voice despite the flight delay of over an hour. Flight attendants in the plane were all grumpy, not pleasant looking bunch. Their sour attitude showed throughout the flight. Inly able to get a select few movies started. Most of the movie links in the “free entertainment” did not work.

This was a horrible experience. For a first class experience, my chair was held together by 3M tape - and I have a photo. The crew weren’t very attentive, somewhat dismissive and forgot my drink and snack, the chair reclined about 3 inches on a 6-hour cross country flight. I was also not informed that there was no lounge available in Newark airport because of renovations, so all around this was one of the worst experiences and I would actively avoid both American and Alaska Air going forward.

They are still charging me after taking 466 and 833 for round trip from AR to to Bradley airport from 19 to 21. Then poor experience. Am hurt and I will say it on social media. Please stay away from this airline. I see in my bank account they are still taking 644. Am trying to stop it. I used to fly United airlines and I suggest that if you don't want extra charges and good service you go back there. American airlines delayed my flight again and I was late for my meeting, no recompensation but charging me over and over.

Boarding was very efficient. Everyone got on board and we got on our way very quickly. It was frustrating that the entertainment app was not functioning properly. I was not able to activate some of the movies offered. The crew on this flight appears to be pretty grumpy. They had no smile on their faces. I felt like they were doing us a favor for being there.

They changed our Gate 5 times, and concourse twice. Changed our seats twice.

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.

What I expected, nickeled and dined and a frontier flight attendant loudly complained about her job and lack of communication as she headed to the gate on her cell phone. Not professional.

As every law enforcement agency I could imagine surrounded the plane and we didn’t disembark for 2 hours and then had to stick around for another hour to go get our personal belongings after leaving them behind and being bused away from the plane, it was scary and inconvenient. We were given no information as to why this was happening. Lack of communication with passengers was disappointing.

After boarding and un-boarding twice over 6+hours, the flight was canceled.

Severe turbulence. Captain never came on to reassure passengers after things settled down.

My first flight was delayed 5 hours. The 2nd flight was canceled til the next day and the never even tried to compensate for it. Worse I was delayed again on the flight the rebooked me on.

Boarding in Orlando was not good. Giant mob at the gate, should have been lines.

Decent clean onboard experience. Okay discount airline experience. Unfortunately, any customer service interactions are difficult and unhelpful. There is no service. Also, a premium seat only gets you premium boarding if you line up first. Once they start general boarding you must go to the back of the line. Not very premium

Everything you need to know for your flight from Washington, D.C. to Ontario

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