SFO - ONT

$33 Find Cheap Flights from San Francisco to Ontario - 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 San Francisco to Ontario departing on 9/6. 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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1 adult, Economy, 0 bags

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Everything you should know

Cheapest round-trip
$57
Typical prices: $116-$209
Frontier
Thu 9/24Mon 9/28
SFO - ONT • Non-stop
Cheapest one-way
$33
Typical prices: $69-$135
Frontier
Sun 9/6
SFO - ONT • Non-stop
Advice from real travelers
AI-powered summary based on content written by travel experts. AI can make mistakes.
United Economy Plus adds up to six inches more legroom than standard economy.
Frontier Economy Bundle adds a carry-on and seat selection to avoid middle seats.
Expert advice
Expert advice
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Expert advice
Top airlines
Cheapest • from $57 (round-trip)
Best reviews • 8.0 score
Airline reviews
Airline reviews
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Airline reviews
+1
Nonstop flights
You can fly direct with Frontier and United Airlines. Average duration is 1h 33m
Direct flights
Direct flights
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+1
Direct flights
Direct flights
+1
Avoid delays
Most punctual • 86% on-time
Best time • Fewest delays
Insights
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Insights
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When to book
in advance
Our data shows that travelers who book at least 2 weeks in advance save around 25% compared to booking last minute.
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When to travel
Cheapest • 28% price drop
Most popular
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Flight Deals

Cheap Flights from San Francisco to Ontario (SFO-ONT)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from San Francisco 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 San Francisco to Ontario

Thu, Sep 24 - Mon, Sep 28
Frontier Logo
12:31 pm - 2:00 pm
SFO
-
ONT
1h 29mnonstop
Frontier Logo
11:38 am - 1:12 pm
ONT
-
SFO
1h 34mnonstop
$57Frontier
Mon, Sep 14 - Mon, Sep 28
Frontier Logo
12:31 pm - 2:00 pm
SFO
-
ONT
1h 29mnonstop
Frontier Logo
11:38 am - 1:12 pm
ONT
-
SFO
1h 34mnonstop
$57Frontier
Thu, Sep 10 - Mon, Sep 14
United Airlines Logo
10:37 am - 12:12 pm
SFO
-
ONT
1h 35mnonstop
United Airlines Logo
6:08 am - 7:35 am
ONT
-
SFO
1h 27mnonstop
$117United Airlines
Tue, Oct 20 - Thu, Oct 22
United Airlines Logo
7:00 pm - 8:31 pm
SFO
-
ONT
1h 31mnonstop
United Airlines Logo
9:25 am - 10:54 am
ONT
-
SFO
1h 29mnonstop
$117United Airlines
Thu, Nov 12 - Sat, Nov 14
Southwest Logo
5:30 pm - 11:35 pm
SFO
-
ONT
6h 05m
1 stop
Southwest Logo
5:45 am - 12:10 pm
ONT
-
SFO
6h 25m
1 stop
$151Southwest
Wed, Oct 21 - Thu, Oct 22
Southwest Logo
3:50 pm - 10:00 pm
SFO
-
ONT
6h 10m
1 stop
Southwest Logo
5:15 pm - 11:15 pm
ONT
-
SFO
6h 00m
1 stop
$151Southwest
Tue, Aug 25 - Fri, Aug 28
Multiple Airlines Logo
12:33 pm - 2:03 pm
SFO
-
ONT
1h 30mnonstop
Multiple Airlines Logo
4:27 pm - 1:00 pm
ONT
-
SFO
20h 33m
2 stops
$204Multiple Airlines
Mon, Aug 24 - Fri, Sep 25
Multiple Airlines Logo
9:33 am - 11:02 am
SFO
-
ONT
1h 29mnonstop
Multiple Airlines Logo
4:27 pm - 10:53 am
ONT
-
SFO
18h 26m
2 stops
$209Multiple Airlines
Tue, Sep 1 - Tue, Sep 15
Alaska Airlines Logo
9:13 pm - 3:47 pm
SFO
-
ONT
18h 34m
2 stops
Alaska Airlines Logo
4:27 pm - 10:53 am
ONT
-
SFO
18h 26m
2 stops
$320Alaska Airlines
Wed, Aug 26 - Mon, Aug 31
Alaska Airlines Logo
9:13 pm - 3:47 pm
SFO
-
ONT
18h 34m
2 stops
Alaska Airlines Logo
4:27 pm - 8:46 am
ONT
-
SFO
16h 19m
2 stops
$320Alaska Airlines
Booking Insights

KAYAK's insights & trends for San Francisco to Ontario flights

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

How much is a round-trip flight from San Francisco to Ontario?

This analysis is based on the cheapest round-trip price found on KAYAK in the last 12 months by searching for a flight from San Francisco to Ontario departing in September.

Flight prices are below average for this route right now.

Flights to Ontario from San Francisco usually cost between $90 and $257 in September.
The lowest price found in the past 5 days was $57 on Frontier (Sep 14-Sep 28).

What’s the cheapest day of the week to fly from San Francisco to Ontario?

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

When flying from San Francisco to Ontario, you should consider leaving on a Monday and avoid Tuesdays if you are looking for the best rates. For your return to San Francisco, you’ll find the best rates on Fridays and the most expensive ones on Sundays.

What is the cheapest month to fly from San Francisco to Ontario?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from San Francisco 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 San Francisco to Ontario is August, where tickets cost $160 (return) on average. On the other hand, the most expensive months are February and March, where the average cost of round-trip tickets is $317 and $279 respectively.

How far in advance should I book a flight from San Francisco 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 San Francisco 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 San Francisco to Ontario, you should book around 2 weeks before departure, which saves you about 25% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 5 weeks before departure.

Expert advice

Expert advice for your flight from San Francisco to Ontario

 
AI-powered summary based on content written by travel experts. AI can make mistakes.
KAYAK teamed up with top travel experts to share the best tips for your journey.
Our travel experts
Stefanie Waldek

Stefanie Waldek

Expert on United Airlines and Frontier

Stefanie Waldek is a freelance space, travel, and design writer based in Saratoga Springs, NY. Her words have appeared in Space.com, Travel + Leisure, Condé Nast Traveler, Architectural Digest, and House Beautiful, among other publications. An expert in aviation and expedition cruising, Stefanie is frequently up in the air or on the sea, likely en route to Antarctica or the Arctic.

Jennifer Simonson

Jennifer Simonson

Expert on ONT

Jennifer Simonson is driven by her lifelong commitment to exploring the globe. Her insatiable curiosity had led her to immerse herself into diverse locations like Oklahoma City and Pismo. Her hotel recommendations are the result of the myriad hotels she's stayed at across her travels. Along her journey, she cherishes engaging conversations with locals, indulging in the finest ice cream, trying her hand at surfing, and embarking on nature-filled hikes.

Blane Bachelor

Blane Bachelor

Expert on SFO

Blane Bachelor is a journalist and editor specializing in travel and aviation who writes regularly for top global outlets. Born and raised in Florida, Blane has worked and lived in four countries, including the Netherlands, where she’s currently based with her family. Her favorite way to get to know a new destination is by running or riding a bike around town – or hearing a spooky ghost story about local history. She will always choose the window seat.

Good to know

Low season

January

Cheapest flight

$33
Best time to beat the crowds but there is an average 14% increase in price.
Most popular time to fly and prices are also 23% lower on average.
Flight from San Francisco to Ontario

When to book flights from San Francisco to Ontario

Are your dates flexible? Find out the best times to travel from San Francisco 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 San Francisco to Ontario

  • What happens upon losing an item at ONT?

    If you have lost your item when traveling to ONT, you can visit the lost and found offices. The offices are in terminal 2 just behind the information desk. The lost and found offices operate from Monday through Friday from 7am to 3:30pm.

  • Are there any electric vehicle charging stations at SFO?

    Yes, there are several electric vehicles charging stations that are easily accessible. The charging stations are located at the domestic garage level 1, Long-term garage 2, and the international garage level 2. The charging stations are available on a first-come, first-served basis.

  • Is SFO safe for kids?

    Yes, SFO airport is child-friendly and you can travel with your children easily. Several nursery spots are located at terminals 1, 2, and 3, international terminal A gates, international terminal main hall, and international terminal G gates. There are shower facilities at the entire airport to enable you to freshen up before traveling with your child.

  • Is safety assured at ONT?

    At ONT airport, there are security screening procedures to guarantee your safety. The security screening commences upon your arrival at the airport. It is advisable to declare all your electronics at the security screening center to avoid inconveniences. The security screening procedures often change; hence it’s advisable to be flexible and adjust accordingly.

  • What is the cheapest flight from San Francisco to Ontario?

    In the last 5 days, the lowest price for a flight from San Francisco to Ontario was $33 for a one-way ticket and $57 for a round-trip.

  • Do I need a passport to fly between San Francisco and Ontario?

    Even though you are not required to have a passport, keep in mind that an official ID is needed to board the airplane.

  • Which airports will I be using when flying from San Francisco to Ontario?

    On your way to Ontario, you’ll fly out from San Francisco. You’ll be landing at Ontario.

  • Which airlines offer Wi-Fi service onboard planes from San Francisco to Ontario?

    Alaska Airlines, Delta, JetBlue, and American Airlines offer inflight Wi-Fi service on the San Francisco to Ontario flight route.

  • Which aircraft models fly most regularly from San Francisco to Ontario?

    The Airbus A320neo is the aircraft model that flies most regularly on the San Francisco to Ontario flight route.

  • Which airline alliances offer flights from San Francisco to Ontario?

    oneworld, SkyTeam, and Star Alliance are the airline alliances operating flights between San Francisco and Ontario, with oneworld being the most commonly used for this route.

  • On which days can I fly direct from San Francisco to Ontario?

    There are nonstop flights from San Francisco to Ontario on a daily basis.

  • Which is the best airline for flights from San Francisco to Ontario, Southwest or Alaska Airlines?

    The two airlines most popular with KAYAK users for flights from San Francisco to Ontario are Southwest and Alaska Airlines. With an average price for the route of $246 and an overall rating of 8.0, Southwest is the most popular choice. Alaska Airlines is also a great choice for the route, with an average price of $247 and an overall rating of 7.9.

  • How does KAYAK find such low prices on flights from San Francisco 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 San Francisco to Ontario.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from San Francisco to Ontario?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Ontario from San Francisco 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 San Francisco 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 San Francisco with another airline. Booking your flights between San Francisco and ONT can sometimes prove cheaper using this method.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from San Francisco 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 San Francisco 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 San Francisco to Ontario

  • Looking for a cheap flight? 25% of our users found flights on this route for $110 or less one-way and $137 or less round-trip.
  • Want to secure a parking spot in advance when traveling to Ontario International Airport (ONT)? It is advisable to book early via the online system. This will enable you to choose your parking spot and ideal date and time. With this booking, there is an assurance your parking spot will be vacant before your arrival. There is tightened security at the parking lot; hence no need to worry about the security of your vehicle.
  • Upon arriving at San Francisco International Airport (SFO), you can get access to free Wi-Fi. The Wi-Fi is strong in all terminals enabling you to watch your favorite movie or game while waiting to catch your flight. You only need to select the SFO Wi-Fi network and launch your browser.
  • You can only travel with your pet at SFO airport if it is kenneled. Your pet will be delivered to the baggage claim area if traveling with it. Before your flight commences, you can take your pet to the relief areas located in terminals 1, 2, and 3. If you wish to import or export a pet at SFO, it is advisable to make prior arrangements to minimize any inconveniences.
  • There is a medical clinic onsite at SFO where you can visit in case you feel unwell. The clinic features state-of-the-art equipment to aid in your treatment. Upon diagnosis, you will be provided with travel medicine to make you feel better. The average wait time is less than 15min, but you can book an appointment before arrival.
  • SFO features an AirTrain that connects all the airport terminals at the airport. Some of the items allowed on the AirTrain include animals, bicycles, and airport luggage carts. The departure time is always indicated on the screens

Prefer to fly direct from San Francisco to Ontario?

 
Direct data is based off flight results for the next 60 days. Find direct flights from all airlines flying direct from San Francisco to Ontario.
Find which airlines fly direct from San Francisco Airport to Ontario Airport, which days they fly and book direct flights.

Direct departures

San Francisco to Ontario

Monday

Frontier,United Airlines

Frontier,United Airlines

Tuesday

Frontier,United Airlines

Frontier,United Airlines

Wednesday

Frontier,United Airlines

Frontier,United Airlines

Thursday

Frontier,United Airlines

Frontier,United Airlines

Friday

Frontier,United Airlines

Frontier,United Airlines

Saturday

Frontier,United Airlines

Frontier,United Airlines

Sunday

Frontier,United Airlines

Frontier,United Airlines

See more direct flights

Direct returns

Ontario to San Francisco

Monday

Frontier,United Airlines

Frontier,United Airlines

Tuesday

Frontier,United Airlines

Frontier,United Airlines

Wednesday

Frontier,United Airlines

Frontier,United Airlines

Thursday

Frontier,United Airlines

Frontier,United Airlines

Friday

Frontier,United Airlines

Frontier,United Airlines

Saturday

Frontier,United Airlines

Frontier,United Airlines

Sunday

Frontier,United Airlines

Frontier,United Airlines

See more direct flights

Reviews of the top 5 airlines serving from San Francisco to Ontario

 
See real verified KAYAK customer reviews for airlines flying from San Francisco 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 San Francisco 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 4229 reviews
8.1Boarding
7.0Food
8.6Crew
8.0Comfort
7.5Entertainment
Airline reviews

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

10.0 Excellentkelly, Jul 2026
SFO - PHX
Read more Southwest reviews

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

It was just okay, no frills, basic transportation with no luxury. No screens on the seats, no water or drinks on a short flight. Full flight but at least it was on time.

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

The flight was delayed for almost an hour. We sat on the tarmac. There was no announcement. Not by the pilot or the crew. And for some reason, there was no beverage service, so even though it was a short flight, we had sat on the tarmac and the extra hour delay made me understandably thirsty. Water would’ve been nice if they had offered it. And for the first time, I forgot to bring my own water bottle. Reminder to bring your own water bottle because you never know if you’re going to get a beverage.

It was a new plane with larger overhead bins & charging ports at the seats.

Our flight to Oakland was great bc the plane was new but it was delayed by 15min not bad at all. Over all it was an 8/10

Luggage was intact and arrived at the destination. What more could you ask for.. haha. The delay in arrival wasn’t SW fault.. just selfish passengers not wanting to check their luggage knowing they were in the last boarding groups

The flight in it self was good. The delays looking for pilots was unexpected.

The plane smelled musky and some passenger would coughing without covering their mouths or were not wearing a mask to stop spreading their germs.. yucky

The plane departed and arrived on time. The crew were entertaining and professional at the same time. Baggage claim was efficient. I was glad to fly with Southwest airlines.

The plane was freezing. A few other customers mentioned how they can’t get their temperature right on their flights lately.

The app booked me on a flight for July 1st as opposed to August 1st like it was supposed to be. No problem with Alaska Airlines, except they took a while to refund my money. But it was as taken instantly. So, yeah.

Not able to get boarding pass for domestic connection flight when check in at international airport. I was told I need to get connection flight boarding pass after I entered US. It us very inconvenient.

Four hour delay. Missed our event. And they offered me $75. Absolutely shameful.

I have been flying commercial for decades. I was in one of the ladder boarding groups, had my bag tagged because they thought there was not going to be enough space for it in the overhead bins. I politely asked one of the attendance if I could try to find a space- she said I could and I did. I then took the bag tag off and gave it to one of the other attendants as I was told to do by the first one. He, in a curt, anal, and disrespectful manner, told me that I needed to take my bag down from the overhead bin and check it. This was a situation I’ve never encountered before. The attendant’s attitude was confrontational and belittling in front of other onlooking passengers as if daring me to challenge him. I am a physician who takes care of patients day in and day out. Not wanting to make a scene, I calmly told him, “do what you need to do.” he took my bag down from the overhead bin, put the back tag back on it, and checked it only to make room for another bag that was also supposed to be technically checked by a following passenger. The same male attendant later came up to me and said “you shouldn’t have showed me the bag tag,” as if conveying that he was just following protocol was a justification for treating me like a kid out of line. I cared about this because it took 15 minutes from my life to then retrieve the bag at baggage claim and it also felt like really poor customer service. I understand the need for protocols. This is also a service industry, and we the passengers are the clients. We should be made to feel welcome and respected and our life in transit made as easy as it can be within reason. This attendant clearly needs to be reminded of that. Of note, an older female fellow passenger sitting next to me agreed with this assessment.

I love Alaska! We arrived on the later side without seat assignments only to find the had oversold the flight by 1. The attendants worked extra hard to find a way for our party of 7 to stay together and we made it on the flight! Loved the free WiFi also!

The he whole flight was very smooth on every aspects.

I paid for wifi and it never worked... it was miserable. I couldn't access my shared files to work on the plane, it didn't work on my phone. I paid for nothing but frustration and continual refreshing, hoping it would work

The flight was excellent and very friendly and helpful staff. Will travel again and recommend to friends. Thank you

Did not have In flight service on my round trip due to turbulence. I did not partake in In flight entertainment. Flight descending into LAX was very turbulent. It would have been nice if the pilot communicated with us during that rough descent into LAX to ease the minds of some of us more nervous flyers.

Crew was absolutely fantastic and we’re so welcoming and friendly ❤️

Flight delayed four separate times. I’m now one hour hours late to landing.

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

Our flight from SFO to MSP was right on time on 11/15/2025. No delays. As we approached MSP at about 8 pm, we circled in the air until 8:40 pm so I don't call that efficient for MSP. I think the captain should announce the delay and why. (as if we all don't know that we are just circling around the area, slowing down, speeding up, slowing down.) Thank you. Marilyn Fischer

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

Thank you for not flipping the plane on the run way. You guys get a 5 star rating for the flight!!!

Boarding is, as it always is… horrible. Gate lice. Slow moving zones. Too many people with carry ons

You need to be a hacker to get the (Free) WiFi

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.

Outstanding service, efficient & friendly crew, flight was safe, comfortable & on time

Flight delayed for more than 16 hrs and no effort was spent to provide an alternate

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

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

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.

Flight was delayed due to the late arrival of the catering truck, which is quite unacceptable. There was a beverage service, but no pretzel, or cookie, or nuts were served in coach.

Airline did not explain reasons why flight was delayed two hours. Explanations were badly needed and rarely provided. Problem seemed to clearly be the airline’s fault and not the fault of the weather or airport.

I was delighted that we were able to get on the 4:40 pm flight rather than our original booking at 6:55 pm!! Other than that, the flight was comfortable and landed early😊

How they treated my luggage was horrible. And foods are not edible… Flight attendants were not listening my request. Etc

I really didn't like anything. Paid for my checked luggage online ($79) and then was told that I would have to paid another $79 for my carry on. Was not allowed to enter the terminal until 3 hours before my flight and when I finally was allowed to check my bag and enter, my flight was delayed 3 times. When I finally landed, we were all instructed to "run off the plane" as they had to do a quick turn around to Las Vegas. Me and several of my flying companions will never fly Frontier again.

The crew was mostly okay. The flight attendant who answered our questions was curt and unhelpful unfortunately. He seemed upset and I understand having off days.

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

Stop changing gates at sfo. When you are elderly going back for it’s not fun.

After 5 hours of delay, they cancelled the flight. Very disappointed

My flight to LA was cancelled. I waited at the airport for 3 hrs saying it was delayed and then all of a sudden it was cancelled. Frontier only gave me a voucher and refund but could not rebook me. Flights on other airlines were too expensive last minute. I had to drive down to LA and didn’t even take my return flight home since I had to drive. One of the worst airline experiences in my life. It’s crazy how airlines can just upend people’s plans just like that.

They wouldn’t let us on the flight even tho we were an hour early. No refund not even our bags that were prepaid

8 hr delay. had to buy another ticket with another airline

They cancelled the flight then did nothing to help us rebook. It was awful - I won’t fly with them again

The truck that was refueling the plane drove away with the hose still connected to the plane and ripped part of the plane off with it

Everything you need to know for your flight from San Francisco to Ontario

Information on your arrival and departure airports