It's all speculation at this point! It is fairly clear that this bird is underwater somewhere and the transponder was off line early in the flight. If they do recover the black boxes then we'll have real data to support some kind of explanation regarding what happened. I'm sure we'll get all kinds of speculation like hijackers, crazy pilots, bombs on-board, or a total airframe failure. I'll take a wait and see on this one, too little information coming very slowly to the general public. If they can't recover whatever "key" evidence is out there we may never know what actually happened.

Joe