The economics tend to be different for most hobbyist pilots since they rent instead of owning a plane. But if you own a plane, my impression from talking to a few amateurs is that it's closer to an RV than to a boat. You need to get the plane inspected and serviced fairly frequently, but sitting in a hangar doesn't place a toll on a plane quite like sitting in water does for a boat. And planes, by virtue of being able to fly, can be stored in cheap hangers in the middle of nowhere. People love living on the coast, so marinas tend to sit on expensive real estate.
