I've done some flying with an instructor on Maui a couple of times. It's a heck of a lot cheaper that getting a tour on a helicopter and more fun since you get to fly (even though not an RV). On Maui, it's always very windy, 15 to 25 mph winds most of the time, so it is best to get with an instructor. There are reporting procedures in place for flying around the islands. I'm sure that you could find the same kind of deal with a plane and instructor on the Big Island.
When I was on Maui in May 2006, I hooked up with RV-6A builder and pilot Greg Grigson who was living on Oahu at the time and he graciously flew over to Maui, picked me up, and gave me an RV tour of Maui. I don't know if Greg is still living in Hawaii, as he said he was getting ready to move to New Mexico. Anyway, here's some of the pics I took.
Maui from an RV
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Shameless plug-I own a condo on Maui that I rent out if anyone is planning a vacation there. Email me for details.)