I first thought to see who this writer is.
From his Newsletter #67:
September 11, 2001 Revisited
September 15, 2004
3. It is impossible to reconcile the documented damage to the Pentagon with the notion that it was struck by a 757 passenger jet. Evidence instead indicates that it was either struck by a missile (and not one launched from a cave in Afghanistan), or taken out with explosives planted within the building.
Red flag. Use caution and fact check all this guy's evidence.
That was the first thing I read of his work. I'm being wary.
Edit: Thx for your down votes, lemmings.