HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
USA

$34+ Cheap flights from Ontario (ONT) to the United States

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 2/6. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LAX
Jan 24 — Jan 311
Sat 1/24
Sat 1/31
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Ontario to USA with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheap flight deals from Ontario to USA

Cheapest flights from Ontario to USA
Explore the most affordable flight options available from Ontario to USA. Find the lowest fares from popular airlines and budget airlines, with prices last updated on December 25, 2025.

This Frontier deal was found by Cheapflights users on 12/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/296:00 pmONT - LAS
Nonstop1h 11mFrontier
Tue 12/304:13 pmLAS - ONT
Nonstop1h 09mFrontier
Deal found 12/22$98
This Frontier deal was found by Cheapflights users on 12/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/306:00 amONT - LAS
Nonstop1h 07mFrontier
Fri 1/28:13 pmLAS - ONT
Nonstop1h 04mFrontier
Deal found 12/22$99
This Trip.com deal was found by Cheapflights users on 12/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/316:00 amONT - LAS
Nonstop1h 07mFrontier
Fri 1/28:13 pmLAS - ONT
Nonstop1h 04mFrontier
Deal found 12/23$101
This Frontier deal was found by Cheapflights users on 12/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/296:00 pmONT - LAS
Nonstop1h 11mFrontier
Thu 1/14:13 pmLAS - ONT
Nonstop1h 09mFrontier
Deal found 12/22$109
This Mytrip deal was found by Cheapflights users on 12/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/296:00 pmONT - LAS
Nonstop1h 11mFrontier
Mon 1/58:13 pmLAS - ONT
Nonstop1h 04mFrontier
Deal found 12/22$143
This CheapOair deal was found by Cheapflights users on 12/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/316:00 amONT - DFW
1 stop21h 43mFrontier
Thu 1/12:00 pmDFW - ONT
Nonstop3h 21mFrontier
Deal found 12/23$147
This Frontier deal was found by Cheapflights users on 12/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/314:22 pmONT - LAS
1 stop7h 32mFrontier
Wed 1/78:45 amLAS - ONT
Nonstop1h 05mFrontier
Deal found 12/24$151
This Frontier deal was found by Cheapflights users on 12/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/246:00 pmONT - LAS
Nonstop1h 11mFrontier
Wed 1/78:45 amLAS - ONT
Nonstop1h 05mFrontier
Deal found 12/22$154
This CheapOair deal was found by Cheapflights users on 12/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/296:00 pmONT - LAS
Nonstop1h 11mFrontier
Fri 1/3012:21 pmLAS - ONT
Nonstop1h 11mFrontier
Deal found 12/23$157
This CheapOair deal was found by Cheapflights users on 12/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/316:00 amONT - DEN
1 stop20h 58mFrontier
Thu 1/88:00 amDEN - ONT
1 stop9h 20mFrontier
Deal found 12/23$163
This Frontier deal was found by Cheapflights users on 12/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/256:00 amONT - LAS
Nonstop1h 07mFrontier
Wed 1/78:45 amLAS - ONT
Nonstop1h 05mFrontier
Deal found 12/22$169
This Expedia deal was found by Cheapflights users on 12/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/316:00 amONT - DEN
1 stop20h 58mFrontier
Tue 1/68:45 pmDEN - ONT
Nonstop2h 27mFrontier
Deal found 12/24$170

Find flight deals from Ontario to USA

Keep the following information in mind while searching for Ontario to USA flight deals. Data was last updated December 25, 2025.

Most accurate provider

CheapOair
3 stars

Most trusted provider

CheapOair
3 stars

Round-trip from

$60
(Cheapflightsfares)

One-way from

$34
(Super.com)

Popular in

December

Cheapest in

January

Average price

$412

Good round-trip deal

$115 or less

Good one-way deal

$87 or less
Provider with most accurate pricing for Los Angeles-New York (NYC) flight deals.
Search Deals
Provider most trusted by Cheapflights users for Los Angeles-New York (NYC) flights.
Search Deals
From Ontario to USA
Search Deals
One-way flight from Ontario to USA
Search Deals
Highest demand for flights based on searches. 5% potential increase in price ($18 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($7 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in December 2025
Search Deals
Price to beat on a round-trip flight from Ontario to USA.
Search Deals
Price to beat on a one-way flight from Ontario to USA.
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Ontario to USA that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated December 25, 2025.
Use the filters below to find and compare flights from Ontario to the United States that are best for you.

Fly from

Ontario

Fly to

USA

Route

Depart

Return

Price

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Mon 2/2

6:20 am-9:40 am

Nonstop2h 20m

Denver Intl

Thu 2/5

10:49 pm-12:20 am

Nonstop2h 31m

$83

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Sat 1/24

3:04 pm-4:16 pm

Nonstop1h 12m

Las Vegas Harry Reid Intl

Sat 1/31

4:17 pm-11:24 pm

1 stop7h 07m

$95

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Wed 1/21

7:15 am-10:40 am

Nonstop2h 25m

Denver Intl

Tue 1/27

9:44 pm-2:12 pm

1 stop17h 28m

$100

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Tue 3/17

1:20 pm-6:30 pm

1 stop5h 10m

Seattle/Tacoma Intl

Tue 3/24

4:55 pm-11:50 pm

1 stop6h 55m

$119

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Thu 1/29

4:03 pm-6:54 pm

Nonstop2h 51m

Seattle/Tacoma Intl

Thu 2/5

9:20 pm-11:56 pm

Nonstop2h 36m

$119

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Thu 2/12

1:10 pm-6:29 pm

1 stop5h 19m

Seattle/Tacoma Intl

Tue 2/17

7:00 pm-11:49 pm

1 stop4h 49m

$119

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Thu 1/22

4:03 pm-6:54 pm

Nonstop2h 51m

Seattle/Tacoma Intl

Sun 1/25

8:15 am-10:59 am

Nonstop2h 44m

$119

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Wed 2/11

11:53 am-2:44 pm

Nonstop2h 51m

Seattle/Tacoma Intl

Wed 2/18

8:05 pm-10:44 pm

Nonstop2h 39m

$119

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Sun 1/18

7:30 am-10:36 am

Nonstop3h 06m

Seattle/Tacoma Intl

Fri 1/30

7:00 pm-11:58 pm

1 stop4h 58m

$129

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Thu 2/26

3:30 pm-6:33 pm

Nonstop3h 03m

Seattle/Tacoma Intl

Fri 3/6

7:00 pm-11:49 pm

1 stop4h 49m

$129

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/25

Showing 1-10 of 60 results
1
2
3
...
6

Best time to book a flight from Ontario to USA

Have a flexible travel schedule? Discover the best time to fly to USA from Ontario with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

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

What is the cheapest month to book a flight from Ontario to USA?

Currently, February is the cheapest month in which you can book a flight from Ontario to USA (average of $18). Flying from Ontario to USA in July is currently the most expensive (average of $49). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from ONT to US?

Find hourly flight availability from Ontario to USA. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated December 25, 2025.

A simple way to save on the total cost of your ticket is to fly from Ontario to USA in the afternoon. If you’re flexible enough to do this you can expect to save up to 30% on your trip compared to booking a flight in the morning.

What is the cheapest day to fly from Ontario to USA?

Use this chart to determine the cheapest time to fly round-trip from Ontario to USA. Price data was last updated on December 20, 2025.

Travelers seeking maximum savings on their Ontario to USA flight should consider departing on Sunday at noon when fares are most often at their lowest. Wednesday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.

How often are flights from Ontario to the United States delayed?

About 12% of weekly flights between Ontario and United States have experienced delays in the past year, with the average delay time being 125 minutes.

What is the most punctual flight time for Ontario to the United States flights?

Historically, flights departing in the morning are less likely to be delayed, whereas flights leaving in the evening tend to experience delays more often.

What day of the week experiences the fewest flight delays on this route?

Saturday tends to have the lowest number of delays on this route, whereas Thursday has historically faced a higher average of delays compared to other days of the week.

Which airline has the best punctuality record on Ontario to the United States flights?

Over the last year, Delta have had the lowest number of delays on this route, with just 4% of flights being delayed.

Reviews of airlines servicing USA

Get insights into the airlines that provide service to USA. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to USA. Reviews last updated December 25, 2025.
Read reviews from past customers who have flown Southwest, Delta, and United Airlines from Ontario to the United States. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,258 reviews

Entertainment

7.5

Comfort

8.0

Crew

8.6

Boarding

8.1

Overall

8.0

Food

7.0

Reviews

1 / 20
10.0
Excellent

William Drew,Nov 2025

SJC - HNL

Flight crew was amazing! Usually they're very good on Southwest, but this crew went above and beyond. I have never ever seen so many rounds of drink service on a flight before.
Southwest
8.0
Very good
4,258 reviews
Southwest
8.0
Very good
4,258 reviews

Entertainment

7.5

Comfort

8.0

Crew

8.6

Boarding

8.1

Overall

8.0

Food

7.0

Reviews

1 / 20
10.0
Excellent

William Drew,Nov 2025

SJC - HNL

Flight crew was amazing! Usually they're very good on Southwest, but this crew went above and beyond. I have never ever seen so many rounds of drink service on a flight before.
Delta
7.9
Good
8,013 reviews
Southwest
8.0
Very good
4,258 reviews

Entertainment

7.5

Comfort

8.0

Crew

8.6

Boarding

8.1

Overall

8.0

Food

7.0

Reviews

1 / 20
10.0
Excellent

William Drew,Nov 2025

SJC - HNL

Flight crew was amazing! Usually they're very good on Southwest, but this crew went above and beyond. I have never ever seen so many rounds of drink service on a flight before.
United Airlines
7.4
Good
9,115 reviews
Southwest
8.0
Very good
4,258 reviews

Entertainment

7.5

Comfort

8.0

Crew

8.6

Boarding

8.1

Overall

8.0

Food

7.0

Reviews

1 / 20
10.0
Excellent

William Drew,Nov 2025

SJC - HNL

Flight crew was amazing! Usually they're very good on Southwest, but this crew went above and beyond. I have never ever seen so many rounds of drink service on a flight before.
American Airlines
7.2
Good
11,062 reviews
Southwest
8.0
Very good
4,258 reviews

Entertainment

7.5

Comfort

8.0

Crew

8.6

Boarding

8.1

Overall

8.0

Food

7.0

Reviews

1 / 20
10.0
Excellent

William Drew,Nov 2025

SJC - HNL

Flight crew was amazing! Usually they're very good on Southwest, but this crew went above and beyond. I have never ever seen so many rounds of drink service on a flight before.
Frontier
5.8
Fair
3,070 reviews
Southwest
8.0
Very good
4,258 reviews

Entertainment

7.5

Comfort

8.0

Crew

8.6

Boarding

8.1

Overall

8.0

Food

7.0

Reviews

1 / 20
10.0
Excellent

William Drew,Nov 2025

SJC - HNL

Flight crew was amazing! Usually they're very good on Southwest, but this crew went above and beyond. I have never ever seen so many rounds of drink service on a flight before.

Related info for your journey

Find useful and relevant information for your journey from Ontario to USA. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airport do you fly from for flights from Ontario to United States?

    Ontario (ONT) is the airport you will fly out of if you book a flight from Ontario to United States. It is only a 3.1 mi journey to Ontario (ONT) from Ontario’s city center.

  • How long is the flight from Ontario to USA?

    Departing from Ontario to USA will take you 2h 20m. The distance from Ontario to USA is about 817 mi. Both multi-stop and nonstop flights can be found to your destination and back.

  • What are the cheapest airlines to fly from Ontario to USA one-way?

    $19 is the cheapest one-way deal found within the past few days, from Frontier. You may also be able to find cheap deals on Spirit Airlines and Avelo Airlines, with prices starting from $22 and $26, respectively.

  • What are the most popular routes from Ontario to USA?

    While some choose either Ontario - San Francisco or Ontario - Seattle/Tacoma Intl, Ontario - Las Vegas Harry Reid Intl is the most popular route from Ontario to USA.

  • Can I find deals for flights from Ontario to USA that include hotel bookings?

    Yes. In addition to deals on Ontario to USA flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Ontario to USA?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Ontario to USA.

  • Can I find deals for business class flights from Ontario to USA?

    Yes. Cheapflights offers flight deals from Ontario to USA by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Ontario to USA?

    Currently, February is the cheapest month in which you can book a flight from Ontario to USA (average of $18). Flying from Ontario to USA in July is currently the most expensive (average of $49). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Ontario to USA

See prices for flight routes from nearby airports that may be better suited for you.
Los Angeles to John F Kennedy Intl flights
San Francisco to Las Vegas flights
Los Angeles to Honolulu flights
San Francisco to John F Kennedy Intl flights
Los Angeles to Newark flights
Los Angeles to Seattle flights
Los Angeles to Dallas/Fort Worth flights
Los Angeles to Cancún flights
Los Angeles to LaGuardia flights
San Francisco to Newark flights
Los Angeles to Las Vegas flights
Los Angeles to Mexico City flights
Los Angeles to Miami flights
San Francisco to Honolulu flights
San Francisco to Ontario flights
San Jose to Las Vegas flights
Burbank to Las Vegas flights
Santa Ana to Las Vegas flights
Los Angeles to Fort Lauderdale flights
San Francisco to Cancún flights
San Francisco to Mexico City flights
San Francisco to Los Angeles flights
Los Angeles to Orlando flights
Los Angeles to San Francisco flights
Los Angeles to Denver flights
San Francisco to LaGuardia flights
Los Angeles to O'Hare Intl flights
Ontario to Las Vegas flights
San Francisco to Miami flights
San Francisco to Santa Ana flights
Los Angeles to Kahului flights
Ontario to San Francisco flights
San Francisco to Dallas/Fort Worth flights
Los Angeles to Hobby flights
San Francisco to Orlando flights
San Francisco to Kahului flights
Santa Ana to Dallas/Fort Worth flights
Ontario to Seattle flights
San Francisco to Seattle flights
Los Angeles to Boston flights
San Francisco to San Diego flights
Los Angeles to San José del Cabo flights
Oakland to Las Vegas flights
Sacramento to Las Vegas flights
Los Angeles to Reagan-National flights
San Francisco to Puerto Vallarta flights
Ontario to Dallas/Fort Worth flights
San Diego to John F Kennedy Intl flights
Los Angeles to Dulles Intl flights
Ontario to John F Kennedy Intl flights

Top 8 airlines flying from Ontario to USA

Discover the top 8 airlines that operate flights from Ontario to USA. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated December 25, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$24Average$162FlexibilityNo cancel feeOn-time65%
FrontierCheapest$35Average$188FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$58Average$404FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$67Average$296FlexibilityNo cancel feeOn-time75%
SouthwestCheapest$97Average$376FlexibilityNo cancel feeOn-time63%
DeltaCheapest$178Average$406FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$186Average$414FlexibilityNo cancel feeOn-time71%
JetBlueCheapest$223Average$331FlexibilityNo cancel feeOn-time62%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.