Here's how to fly for free (almost). Sign up for an American Airlines Credit Card:
http://www.aa.com/i18n/AAdvantage/earnMiles/beyondTravel/creditDebit/citi-platinum.jsp?anchorLocation=BP-Plat1&title=citi
They have a special going on if you spend $3000 in the first 3 months, you get 50,000 mile. They are partners with Hawaiian Airlines, and you can book inter-island flights for 5,000/segment. The card costs $95/year, but the fee is waived for the first year. You do have to pay $5.60/segment in fees, so it's not completely free, but you won't beat that price. We booked our flights from Kauai to Maui next February that way, and have plenty of miles left over for future inter-island flights.