Why does everyone say this? You create 'terrorists'; have them hi-jack a plane, and crash it. It really takes what, 50 people MAX, including the terrorists. One Mission Planner, however many terrorists...a few benefactors, some intelligence guru's; and that's pretty much it. Maybe a guy or two planted to interfere with birds going up to shoot down the planes but even that is a bit questionable as to 'needing'.
Everyone wants to say that oh the NYPD would have had to have been involved and the fire department would have known...noooo...they reacted as they normally would.
Not saying I really believe it was an act by my own government...or fine, part of my own government; but I just wanted to point out that not everyone and there mother would have been involved...really just a few guys and gals in the grand scheme of things.