The technology for autonomous aircraft is developing fast, driven mainly by the military, and it seems likely that within a few years we'll be sharing our civil airspace with remotely piloted drones. It also seems likely that the last fighter pilot has already been born. But what about the last GA pilot?
Given the technology we have today, the fully-autonomous GA airplane seems well within reach. Autopilots are more and more sophisticated. Cirrus now offers a system that can sense if the pilot seems to be hypoxic or in danger of stalling, and the airplane will fly to a lower altitude or stabilize itself. It's easy to see from here to a time when a traveler can just climb into the cockpit and type in a destination, and the airplane will do the rest, communicating with a smart grid of airspace controllers and weather observers (who may be human or automated).
I expect that most pilots contemplate such a day with dread. What's the fun of flying if you're not in control of the airplane? But I'm not so sure. I think it could launch the next great age of aviation. Think of all the people who could make good use of a small aircraft if they didn't have to invest so much time and energy learning to fly and keeping current. The demand would bring down the unit costs, and that would drive demand even higher, driving costs ever lower and stimulating more innovation. It would almost certainly be safer. The view would still be spectacular, the luxurious convenience of travel on your own schedule would still be the same.
Sure, pilots would miss the sense of accomplishment that comes with a smooth landing or that first solo. But sport flying can continue, like it does today, at grass fields and backcountry strips and lake resorts where trikes and Cubs and floatplanes perpetuate the joy of flight. It seems to me that when airplanes fly themselves, it won't be the end of GA, but the start of an exciting new chapter.