Q: What do you get when you cross an airplane with a magician?

Q: What do you get when you cross an airplane with a magician?
A: A flying sorcerer.

This is a riddle in the standard Q and A format, and also a pun. The joke is based on the words "Flying Sorcerer", which sound a little bit like "flying saucer". A wizard and a sorcerer are both magic users, and sometimes are considered to be synonymous. A flying saucer is a type of imaginary air transport, which can hover, and is manned by aliens.

At this point, the pun sort of falls apart, since a wizard is not an alien.