Look at this
http://www.youtube.com/watch?v=HZgo2puA7RY
This is a video of a stunt pilot who, in real life, is an airline pilot. His act at air shows is to pretend that he is a drunken spectator who rushes from the stands and jumps into a Piper Cub and takes off without any understanding of how to fly a plane. The Piper Cub is a modified one, as it is actually specifically built to withstand an enormous amount of stress and has a very powerful engine.
This type of stunt is actually the most dangerous of air show acts, because of the low altitude at which the pilot performs. Obviously, this pilot possesses unbelievable skill. Check out the landing at the end - that is special!!!
… and do not try it at home!