One of my work colleagues has relatives near Pittsburgh who've maintained that the jet there was 'definitely' shot down by the US military: they saw it happen. The sky was apparently full of aircraft for a while, they heard gunfire and saw the damaged 'plane go down.
Was it in Pittsburgh proper? Gosh - I didn't hear about that one. Of course, we haven't got cable, so there wasn't much news coming into the apartment. The last I'd heard was a crash in Somerset county.