The whole thing smacks of something sinister. Eliminating the passengers is easy enough, at the altitude they were flying. All a hijacker would have to do is pull the breakers for the oxygen masks and open a port. They'd be dead within a minute at 30,000 feet. If the transponders were shut off then after about 100 miles over water they would basically be invisible. (I'm no expert but I have picked the brain of a friend who was in the military, and now works on aviation electronics for airlines and the government)
I'd like to know who was on that plane, more than what happened to it at this point. That could definitely answer some of the how/what/where questions.
I haven't read extensively on this yet. Has China responded? (Just curious)
Of course, I could just be cooking up my own conspiracy theories.