David C,
Have you ever been to Washington, DC? Do you know where the Pentagon is? There are major roads, highways, all kinds of public buildings around it. Are you saying that within seconds of the crash that the FBI or CIA or something came in, planted all this evidence (plane parts, human parts) in front of hundreds, if not thousands of witnesses, and managed to silence all of these people?
Look at the pictures on the websites linked below. You will notice media people, hundreds of fire department and medical personnel, and many ordinary citizens. You will notice major interstates with cars going by. Everyone of them has been silienced?
LINK 1
LINK 2
Yet, all of that is disproven because of one blurry (yes, blurry!) photo that YOU say shows some plane that isn't a 757. Maybe you need to step back from this and think how illogical your idea is.