As Andy is alluding to here, remember -- the only evidence of an actual plane left in NY at 9/11 was some landing gear that popped off at skyscraper-level and mountains and mountains of paper scattered in the air and billows of flame that made out the face of Satan.

So you can start asking funny questions, like why didn't all that paper just burn up in the jet fuel that ran through the hallways in a big fireball?
...questions that seem plausible on the surface, if you leave things on the surface. Throw in some Dust Brothers from the soundtrack to
Fight Club, a few quotes attributed to "witness testimony", and viola!... it's unfortunately not too hard to come up with these.