Some of the things said dont add up. Some things said were later retracted. I think some of the confusion on that fateful day is to be expected. No one ever anticipated a terrorist attack of that magnitude.
The only reason I can think of for the gov't to NOT tell us if they did in fact shoot down flight 93 is the possiblity of the *heros* taking flight 93 out of the equation.
How could you not shoot down a civilian airliner that had obviously been hijacked and was headed towards Washington DC or any other heavy population center?
I admit, I would not relish the thought of being the one to have to issue such an order, nor would I want to be the one to have to carry out such an order.
That said, links provided in this post have not provided any proof of flight 93's demise, they only speculate.