evil wizzard: it all becomes a matter of priorities. Stick with the free-fall speed of the collapse of the three WTC towers, with massive chunks of steel hurtled as much as 500 feet horizontally, and 1% non-metallic debris; having come down in rhythmic and symmetrical fashion. Look at the first pictures of Shanksville and then try to reconcile it with the bogus Popular Mechanics piece. Then the total non-appearance of the twin titanium Rolls Royce engines at The Pentagon. Add to that Cheney's power grab of the reins of NORAD (totally unprecedented), the stand down of the nation's inner defense system, including the shut down of The Pentagon's missile battery and you have an overkill (Hmmm, quite a pun.) of proof for your friend.
"When in doubt, empty the clip."