Determine in advance which islands you want to travel between. According to the website andhawaii.com, if you book your flights well in advance, they may cost as little as $70 one way or much as $180, as of 2010. Booking in advance also will help you to determine if you will be flying on a major airline or a privately-owned prop plane, and will help you to pack accordingly. Major airlines include Hawaiian Airlines and Go! Airlines. Minor airlines include Island Air, Pacific Wings and Mokulele Air.