$105 Cheap Frontier Airlines flights Chicago (ORD) to Islip (ISP)

Set the "Price (lowest to highest)" filter on Expedia to find cheap Frontier Airlines round-trip flights from $243 from ORD to ISP. Affordable one-way tickets from $105 are also on offer.**These prices were available on Expedia within the past 7 days, for flights departing within the next year. Prices and availability are subject to change. Additional terms apply.

Start searching one to three months ahead of your departure date to find cheap fares on Frontier Airlines flights from O'Hare Intl. Airport (ORD) to MacArthur Airport (ISP). You can save 25% by booking your domestic flight 34 to 86 days in advance versus last-minute reservations made 6 to 12 days out. You could also cut costs by buying your fare on a Sunday, as it's 6% cheaper on average than a Monday, the most expensive day to book.* Get your timing spot on, and you can enjoy significant savings on domestic trips.*Ideal booking window recommendation is based on average round-trip ticket prices for January through November for 2024. Best day of the week to book recommendation is based on average round-trip ticket prices for January through October 2024. All data sourced from ARC's global airline sales database.

Sort your results by "Morning" and "Early Morning" to browse the earliest departures from ORD to ISP. Jetting off early means flight cancellations are less likely.**Most reliable time of the day recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.

Fly from ORD to ISP with Frontier Airlines and look forward to a range of perks starting with a rewarding loyalty program. When you book through Expedia as a Frontier Miles and One Key™ member, you could also earn OneKeyCash™* to spend on select future travel purchases.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.