I have three degrees in aeronautical engineering. You are an excellent example of someone who can't figure that out. But knowledge of aviation does not bear on the sheep reflex of people who are (1) trapped, (2) not in control of anything, and (3) are vulnerable to what they are being told. The plane that crashed in Pennsylvania gave a running account of the scenario. There is no reason to think that it was any different in the other 3 planes.