Thumb Score: +6 Southwest Airlines have round trip airfares travelling to and from Islip Long Island NY (ISP) and Palm Beach FL (PBI) for $140, nonstop. On Southwest, you may have a personal item, a carry-on bag, 2 free checked bags and free change/cancellation. There is no seat selection. Travel Availability:Departs ISP: Nov 17, 19, 21-22; Dec 8, 13, 15; Jan 14-15, 21-22, 28-29; Feb 4, 25 Departs PBI: Nov 15; Dec 6; Jan 14-15, 22, 28-29; Feb 4-5, 11-12 To get this airfare deal, use the dates and book on Southwest Airlines [southwest.com].