Also, a good friend's mom who grew up with the mayor in the PA town where flight 93 went down was told by that mayor it was indeed shot down by the Air Force. Supposedly it was headed to the white house and they didn't want to take any chances and it was a good 'hero' story to rile up the troops.
I'd think it would be unnecessary to make up the story. Air Force protecting us from terrorists is a pretty good story, though maybe not as clean as passengers taking the situation into their own hands. Plus, the passengers either called the family members and told them what they were doing or they didn't. I don't think a typical middle class wife whose husband just died in a plane crash would be able to lie about something at a time of crisis because the government told her to and keep it together through the tragedy.
Also, isn't it fishy that not one but three steel buildings collapse by fire when never one in history had ever done before?
FWIW, my father in law is an architect and the way it happened made perfect sense to him. Full tank of burning jet fuel is hot enough to stress the beams enough that they break. Once one floor collapses, the weight of the others causes the whole thing to telescope.
Not buying the cospiracy thing.