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.
That is an Egyptian vulture, a Neophron percnopterus. Mason has been rescuing them since he was 11, and now he keeps doing that and trains them as his fly instruments. This is how it works: He carries one at take off. Once he is airborne, he frees the raptor, who starts looking for warm, ascending air currents.
Mason—who usually flies with another person, charging $147 per flight—steers the paraglider following the vulture for a while, enjoying the paths traced by the bird. Every now and then, he will use a whistle to call the vulture, who returns to him from behind the paraglider, landing on his arm like an F18 would land on an aircraft carrier.
Mason has other birds too. In fact, he rescues, nurtures, and then frees them into the wilderness as soon as they are in good shape.
Yes, I so want to do this too. Badly. [SFGate]