That's possible. Why they would be scared though, I cant figure. If anything, they would have used the footage to help gain the momentum needed to gain support for the war. Look at the impact of the world trade centre footage. It was a difficult thing to stomach. The footage of that was almost totally responsible for getting the people to agree to war.
Don't forget, they pulled the footage of the planes going into the building off of the news within a day or two. Expert psychologists said it was too emotionally damaging for people to see.
To be honest, Ive no idea why they wont show the footage. Ive heard the missile theory. Ive also heard the remote control plane theory. It all sounds like total horse shit and that includes the government policy of hiding the footage they obviously own.
I have a theory that a pentagon employee got drunk and streaked through the yard right before the plane hit. That's why they don't release the footage.