Were any bodies from the four aircraft recovered?
If there weren't any bodies on the aircraft, this is the reason it was said that all planes would burn to ashes.
To hide the fact that there weren't any passengers on board.
So, what about Flight 93?
Why did it stray from its' intended target or did it never have an intended target to begin with?
Was it used merely for muddying the waters and as evidence that hijackings actually took place?
Did it land safely in Cleveland and the passengers whisked away and a dummy shot down in Shanksville?
It's possible that ANY COMMERCIAL Plane can have it's navigational controls hi-jacked, this is nothing new,Classified Technology of all sorts exist out there.