There are a number of posters on this website who had personal connections to the aircraft and crew involved in the WTC and Pentagon attacks, as well as Flight 93. Don't look for much sympathetic reaction here to ignorant, unfounded conspiracy thoughts.
The conspiracy nuts won't be swayed. As long as they can sow doubt in their own minds, the truth is irrelevant.
A few years ago someone directed me to a chemtrail site which purported to have pictures of the aircraft. One in particular, I knew; it was a shot inside a firefighting aircraft and I knew it well, because I flew it. The site claimed it was a secret picture of chemtrail equipment. It was actually a fire retardant dispensing system inside a C-130. Against my better judgement, I pointed that out, but to the web site maintainer, it only made me one of the conspiracists. The truth didn't matter; it was all about what he wanted to believe.
Those claiming 09/11 conspiracy theory are no different. The notion that an aircraft did not hit the pentagon, or that the destruction of the twin towers was not the result of a terrorist attack are utterly ridiculous. To those who fantasize about false flags and coverups and conspiracy (which does exist in the real world...just not everywhere one turns), the truth will never matter. The allure of the fantasy is just too strong.