I think if UA93 was shot down, it would have been announced publically. Maybe even make them look good - willing to make difficult, horrible choices. Come on, the pax were gone anyway, if the plane was shot down it wouldn't have improved their chances which were nil, but it would have saved the lives of god knows how many on the ground. As it happens they didn't need to make that decision (although I understand fighters were en route).
The US gov't lost so much credibility because of the suspicious nature of the TW800 747 crash (which I firmly believe was a mechanical fault), if there was any evidence leaked about a shoot-down of UA93 then it would give the conspiracy theorists much more mileage re TW800. I firmly believe the American people would accept the shooting down of a hijacked airliner that was on a suicide mission, I would rather lose (with an extremely heavy heart) 50 or 100 people on a BA 757 than lose them PLUS the Houses Of Parliment / Sellafield, may god forbid. The phone calls from the flight suggested the pax knew the nature of the hijacking cos both WTC towers had been hit, and they said they were going to try to take over the flight.
Whatever the target, I believe this flight came down cos the passengers got onto the flightdeck and either whoever was flying lost it, or no-one was flying.
What a day.