It's not just the witnesses, but yes the fact that every single eyewitness say they saw a plane hit the Pentagon, does contribute to my belief. Just as all the American Airline plane parts (including the black box for AA flt 77) found in wreckage contributes. Just as dna of the passengers contributes. Just as radar tracking from 4 different sources contributes.
Then the lack of any evidence to believe otherwise also contributes. No parts of anything else found at the scene. No evidence of American Airlines flt 77 going anywhere else. No real evidence whatsoever.
Yes I question the official story of the WTC collapses. That's what started me researching 9/11 many years ago. I also highly suspect that the CIA and/or Mossad infiltrated and aided the hijackers. This to me is the mo. Like with WTC in 93 and OKC bombing, those groups were infiltrated, put up to the action, and then aided to do it. And I think 9/11 was done the same.