What is the likelihood that the side of the Pentagon that was destroyed on 9-11?

i have just watched a movie about it i am from Canada and from what i gathered there id a very high chance that the government had something to do with all the attacks. whether there was someone like a double agent inside or whether the us government just wanted to start a war on Afghanistan, there was someone inside who ordered certain people to not be near the places that got hit on 9-11.