$214 Cheap Flights from Islip (ISP) to Ontario Intl. Airport (ONT)

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Islip to Ontario Intl. Airport Flights

The cheapest times to fly from Islip to Ontario Intl. Airport

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from Islip to Ontario Intl. Airport are during the month of December. You can find some of the cheapest flights from Islip to Ontario Intl. Airport with Expedia's search tool and vast selection of airlines.

The best time to book a flight from Islip to Ontario Intl. Airport

Sunday is one of the best days to book for cheap flights from Islip to Ontario Intl. Airport: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

How to find cheap round-trip tickets from Islip to Ontario Intl. Airport

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from Islip to Ontario Intl. Airport in 2026. You can also book with separate airlines for your outbound and return journeys, from $214 one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap Islip to Ontario Intl. Airport flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

You could also save big by booking one of Expedia's vacation packages. Bundling together your Islip to Ontario Intl. Airport airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

*Terms apply.

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

Frequently Asked Questions

How much does a flight from Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) cost?

You can find cheap one-way flights from $214 and cheap return flights $523 Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) with Expedia. Roundtrip flights usually range from $1062 to $2690. Flight prices vary based on the month and day of the week you want to travel, as well as the airline and how far in advance you book your ticket. Filter your search on Expedia by "Price (lowest to highest)" to see the cheapest fares first, and use the Price Tracking tool to receive alerts when Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) ticket fares go up or down.

*Typical price ranges based on flights available on Expedia in the last year. Prices include multi-airline options.

What is the cheapest month to fly from Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?

The cheapest month to fly from ISP to ONT is December when demand is low. Traveling in off-peak or shoulder months is usually a good way to secure cheap tickets, just remember to avoid flying during holidays if you're able to. Use the calendar view in your search to see which months have low fares on this route.

Which airlines fly direct from Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?

Enter ISP to ONT and your travel dates, then apply the 'Nonstop' filter to see only direct flights.

What is the cheapest airline that flies from Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?

Southwest Airlines is one of the cheapest airlines offering connecting flights from MacArthur (ISP) to Los Angeles - Ontario Intl. (ONT), with round-trip tickets starting from around $1,376 with a layover in Orlando Intl. (MCO). Use Expedia's search tool to compare the prices and schedules of airlines that fly this route to find the best option for your plans and budget.

*Prices based on flights available on Expedia in the last year.

How do I find cheap flights from Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?

To find a cheap flight from Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.), be flexible with your dates. Traveling outside of peak vacation months and booking a mid-week flight can help you save. Early morning and late night flights are often more affordable, too. Expedia allows you to compare flight times, airlines and routes all in one place to find low fares. You can also set up Price Tracking and receive alerts when fares go up or down.

What is the best time to fly from Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?

The best time to fly is usually mid-week (Tuesday or Wednesday) and during early morning hours as flights tend to be cheaper, less crowded, and generally more on-time. Avoid major holidays and peak vacation seasons for smoother travel. Combining off-peak days and hours often gives the best combination of cost, comfort, and convenience.

What is the earliest flight from Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?

The earliest flight from MacArthur (ISP) to Los Angeles - Ontario Intl. (ONT) usually departs at around 5:30 AM, operated by Southwest Airlines. This service is seasonal and active in October. An early flight can help you make the most of your day in California. To compare early flights on Expedia, select the "Early Morning" and "Morning" filters in your search.

What day of the week has the most flights from Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?

You'll usually find the most flights from MacArthur (ISP) to Los Angeles - Ontario Intl. (ONT) on a Wednesday, with around 5 flights available. This gives you plenty of options for your travel plans.

What are the most popular departure times for flights from Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?

The most popular departure times for flights from Islip, NY (ISP) to Ontario, CA (ONT) are in the early morning, from 6am to 9am. About 64% of passengers prefer this time window. Many major carriers, including Southwest Airlines and United Airlines, offer flights during this window. This timing works well because it allows you to maximize your day in Ontario upon arrival.

How long does it take to fly from Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?

Flights from ISP to ONT with one stop typically take around 9 hours 20 minutes, covering approximately 2,458 miles. Keep in mind that actual flight times can vary due to wind patterns, weather, and air traffic.

Can you fly business or first class from Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?

Select the "Business class" and "First class" filters when looking for ISP to ONT flights on Expedia. This is the easiest way to compare prices, routes and flight times for your trip.

How do I earn miles on a Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) flight with Expedia?

It's easy to earn miles on a Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) flight when you book with Expedia. Before you confirm your booking, simply select your frequent flyer program and enter your program number. As a member of One Key™, you can also earn OneKeyCash™* on top of your airline miles when you book with Expedia.

*Excludes taxes and fees. OneKeyCash is not redeemable for cash and can only be used on Expedia and other participating brands.

What airports do you fly into for Ontario from MacArthur (ISP)?

From MacArthur (ISP), you can fly into Los Angeles - Ontario Intl. (ONT) to reach Ontario. Some flights may connect through major hubs like Logan Intl. (BOS), Orlando Intl. (MCO), Baltimore Washington Intl. Thurgood Marshall (BWI) before reaching Ontario. Compare routes and airports on Expedia to find the best flight options for your travel plans.

Is it cheaper to buy a plane ticket from Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) at the last minute?

Typically, booking a last minute flight from Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) will be more expensive than booking in advance. As the departure date approaches, there are usually fewer seats available which can drive up the cost. However, if there's some wiggle room with your travel dates and times, you could bag a cheap last-minute fare.

Is it cheaper to book a Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) flight and hotel package?

Securing a Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) Los Angeles Vacation Packages is usually cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your travels all in one place. Select from our extensive range of stays and then add flights, activities and car rentals to your booking. Bundle everything together, and you could save hundreds of dollars.

Can I cancel or change the date of my flight from Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.)?

If you booked your Islip, NY (ISP-MacArthur) to Ontario, CA (ONT-Los Angeles - Ontario Intl.) flight within the last 24 hours, you may be able to modify or cancel it without any fees. Depending on the airline and the type of ticket you have, additional charges may apply for changes beyond this timeframe. Airline policies and contact information can be found in your itinerary or confirmation email. Or, head to our Customer Service portal if you'd like more information.