Steven Stills is the one who doesn't act deadly seriously in Airplane. No, wait, that's Stephen Stucker. I don't know who Steven Stills is. He's probably a tramp or something.
Yes, the mystery of who Steven Stills actually is has been solved. I quite simply did an AltaVista search for something along the lines of "Stephen Stills". He's a guitarist, or something. The photo to the right was taken in 1969 at a place where he regulary played. You can see all of his fans in the background (the slightly blurry bit behind him. Or are they trees?). The pic to the top-left is Phil South. You can see that, quite obviously, they look nothing like each other. Oh, damn. I've just realised I spelt Mr Stills' name wrong. Perhaps I got the wrong bloke. Where's that AltaVista address gone...?