$211 Cheap Frontier Airlines flights Milwaukee (MKE) to Islip (ISP)

Finding cheap one-way Frontier Airlines flights from MKE to ISP from $211 on Expedia is a breeze — just filter by "Price (lowest to highest)." Or check out our affordable return fares from $239 for your next adventure.**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.

To find cheap Frontier Airlines fares from General Mitchell Intl. Airport (MKE) to MacArthur Airport (ISP), start searching one to three months before your intended departure. Securing domestic flights 34 to 86 days in advance could save you 25% compared to booking just 6 to 12 days ahead. The day you book can also influence the overall cost. Sunday is usually the most affordable, while Monday is often the most expensive for domestic flights. You can save 6% on average by booking on a Sunday.**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.

Search Frontier Airlines's earliest flights from MKE to ISP by selecting the "Morning" and "Early Morning" filters. Not only will you arrive at your destination sooner, early departures also have a 20% less chance of being canceled.**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.

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