"You never heard such theories, but none of them could be proved..."
(Peter Case, 'Walk in the Woods')
I had always hoped that the plane was hijacked as part of some conspiracy out of a Clive Cussler or James Bond story, and all the crew and passengers were safe on some remote island while some villain used the plane for nefarious purposes. disappointingly, it appears the plane and people were indeed lost.
sad to think, considering how big the ocean, we may never know.
also sad to think that the Pentagon has info that would answer this, but can't / won't release as it would reveal trade secrets.
one theory is pressure leak and everyone fell unconscious from lack of oxygen, in which case they wouldn't have suffered much.
once known as El Goobero