(this testimony is confirmed
here and here. See also this comment by the retired high-level CIA analyst mentioned above).
So how was a hijacked plane able to slam into such a heavily-defended building long after it had become apparent that a terrorist attack was being waged against America with hijacked airplanes, and given that the military was actually tracking the airplanes? Why did the Vice President of the United States, in charge of counter-terrorism on 9/11 (see this Department of State announcement; this CNN article; and this essay), watch the plane approach from many miles away but say “the orders still stand”, when such orders led to the plane not being intercepted?
There are additional questions about the attack on the Pentagon. However, we believe that these questions are largely distractions from the vital questions raised above.
We believe that it is very possible that when the videos are finally released, they will clearly show that the hijacked Boeing 757 was flown in a standard manner by the hijackers and crashed into the Pentagon. However, according to those who have watched the government videos released to date, such footage is not conclusive. While we are not convinced that anything other than a Boeing 757 hit the Pentagon, The government should release all of the relevant videos to give a full accounting.
Other claims have also been made about the Pentagon (see, for example, the claims made here). However, we believe that the questions regarding the government intentionally allowing the aircraft to hit the Pentagon, discussed at the top of this webpage, are the most important.