Kamikaze King wrote: Sir McFate of the Clan NLR!
From the information Zup posted when he first introduced the different hit points on the planes, the one shot kill is definitely possible. That being, a clear shot to the pilots head. I haven't yet experienced it myself, but I have been told a few times by other players that I have killed them with one shot but it has always registered on my screen as three or four hits. From what I have experienced I have come to the conclusion that lag definitely has a part to play! 
Hey (GI) KK,
The trouble is that Zup never lined out his design. In the quotes on the first post, everything written in blue was by me. Zup just said that he'd been working on "something like" it. It was a few days later that the planes took more than two hits. At first it seemed like it could take anywhere from 2-5 hits. I never saw a one-hit-kill unless there was some lag involved.
I think it would be cool if a hit to the pilot would send him back to spawn point. No chute, no tank. Dead.
(That's what happened with the Red Barron, only he managed to land and shut down before dying.)
Maybe there will be more resolution in DF2.