I haven't wanted to look. There are Always conspiracy theories. Meanwhile there are stateless death cults with money (and military training, thanks to the 'cold war'), that could hijack airplanes. Nobody has better incentive than supernatural belief that this life, this planet, doesn't matter. Conspiracies will invariably sprout, after the fact, at least, as powerful cowards cover up their stupidity and negligence. So, you will have to show me what advantage any pragmatic entity, building anything (even an evil empire), would get from this elaborate tableau that they could not have gotten more easily, and with less, random collateral damage.
Still, it has been a long time for the pentagon attack to remain so fuzzy, and building 7, and the motor parts... I can no longer avoid it. I will have to read on.