I'll admit up front, I've NEVER been a real big fan of this 'paranoid/schizoid' suggestion from 'certain members of the tinfoilhat community' that there were 'no planes' used on the September 11th 2001 'terrorist attack on WTC 1, 2 and Pentagon'.
They're known (derisively) as NO PLANERS, and yet....
...I dunno, it's fairly intelligent investigation/analysis.