An interesting prospect is that a bunch of autonomous cars on the freeways might have a meaningful impact in preventing traffic jams (specifically those "phantom jams") [0] simply by driving in a calm and pondered way always at a constant distance.
Flying used to be like this - my grandpa had 3 airplanes, used one to fly a calf back to his farm. But flying got regulated till it's quite rare to meet a casual pilot with his own plane.