I was going to let this one go, but the tinfoilhatwearers are trying to prop there side up any way they can, so i'm going to add something i DO know.
  My better half's granfather worked for Pratt & Whitney/United for over 40 years as a trouble shooter, and was a lead consultant in the air industry until he passed away, involved with many air crashes.  After 9-11 he was called in to look at all of the issues of the crash, and parts & pieces that were found.  His take, and the take of the others that he personally knew was, that the planes were passenger planes blah blah blah.  He spent a lot of time on this, and was convinced the final reports were accurate.  I don't believe for a minute that he tried to cover up anything, or was mis-led about anything.
  Now, you can dis-miss all of this to fit your agenda, but i'm not going to as there's just too much evidence to support it and him!
  DM