The problems I have with the "no plane" theory have to do with complexity. You've got a bunch of people who claim they saw airplanes slam into the buildings. You've got films of at least one plan slamming into a building. You've got four missing planes with a few hundred passengers.
The "no plane" theory says that somehow the planes that people saw hitting the building weren't really there - holograms, or whatever. However,
*something* brought those buildings down. So OK, it was a plan hologram and high explosives inside the buildings that brought them down. Fine. And
something else happened with the Pentagon - again, no plane, but something that made a big hole in the building. Some say it was a missile. OK,
fine, why not?
But then you've got plane #4, which didn't do much of anything except crash. Why? Why even bother with it, if it didn't hit something
Where did these four planes and hundreds of passengers go? And who go to all that trouble, when you could just load up some planes with fuel and fly
them into the buildings and get a pretty horrible result doing that?
I'm thinking Occam's Razor here, the simplest explanation is to be preferred. I don't see any good evidence that planes weren't used, but they
still disappeared. Too much complication, too many chances for there to be a glaring error that they wouldn't be able to hide. It looks to me like
someone decided it would be a good idea to fly some planes into buildings - maybe terrorists, maybe our own government, who knows? But I just can't
see a convoluted conspiracy to pretend that planes flew into buildings, and to demolish those buildings with explosives, and then have to get rid of
the real planes and people on them.