To save on the cost of your flight from Illinois to Islip, New York, book at least 46 days before your planned departure. Booking around this time can save you about 82% on the cost of this flight compared to booking a flight leaving this week. We have found prices from $250 if you need a flight within two weeks. For flights within the next 72 hours, you can find tickets from as low as $307.
Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Illinois to Islip, New York as you normally would.