The more I read from 9/11 truthers, the more I start to realize that their entire argument boils down to looking at photographs or videos of the attacks and saying "Well that's not what I'd expect to happen!"
Take the nuts who think that a missile hit the pentagon, for instance. You'd have to believe that the government hijacked a plane with ~58 people on board, disappeared the entire plane along with all of its passengers, flew another aircraft capable of firing a missile to the Pentagon (which is close to a crowded highway), hit the Pentagon with said missile, placed large amounts of airplane wreckage at the site, and did all of this in broad daylight when many of the above activities could be clearly seen.
That plan by itself is pretty damn stupid, but it's even worse when you realize that it would have been infinitely more easy to just crash the plane into the Pentagon. The second scenario wouldn't even contradict their broader beliefs about a 9/11 conspiracy; the only thing they would have to abandon is the belief that a missile struck the Pentagon. Yet they still cling to that view, as convoluted and ridiculous as it is, because they saw a few pictures of the Pentagon lawn after the attack and, well, it just doesn't look how they expected it would.