I'm in Hawaii and I'd like to know how to cheaply purchase inter-island flights using frequent flyer miles. They typically cost about $135 roundtrip. I have lots of United Airlines miles and I can usually book an award seat for 10,000 miles. But I want to do better. How about the Barclays US Airways Credit Card? It has a 40,000 mile signup bonus and claims to give a 5,000 mile rebate on all award travel. Since US Air is in the Star Aliance, can I use that credit card and book inter-island flights for 5,000 Mileage Plus miles? That would be the normal 10,000 miles, minus the 5,000 mile rebate. Using 5,000 miles instead of 10,000 miles could be a big win for me since I often fly inter-island flights. Does anyone know the answer to the above, or how I can find it?