Parahawking is falconry in flight. Just with a vulture. There's only one place in the world you can do it: Pokhara, Nepal and doing it is as awesome as it sounds.
This seems straight out of a Terry Gilliam film. The guy flying with the two really big birds is Scott Mason, who uses them to detect thermal currents to fly his paraglider through the skies of Nepal. It's called parahawking.