The "science" used in these reports is similar to the "science" they're using on Finding Bigfoot.
I was a 9-11 first responder via AWACS aircraft, and I think these conspiracy theorists are off their rockers. Although I was tasked to fly to the Pentagon / White House, we had comm/data links with the other bird in NYC, and of course intelligence briefings ad nauseum before and during both the Afghanistan and Iraq wars I flew in.
As our business was command/control and intelligence, we probably had the biggest picture/perspective of anyone. I can tell you nothing "fishy" like proposed by these armchair crazies happened, it was a terrorist attack, as advertised, not some self-inflicted catalyst/excuse for war.
The 911 Truthers can't handle the truth of the 911 conspiracy committed by Al Qaeda. They truth scares them or disturbs them at a fundamental level. The raw reality of what happened is more than they can handle.
A real enemy with a real agenda is more than they want to address.
On second thought, the truthers probably just like non-falsifiable theories that make no sense to everyone else.