Good film. What I really respect about it is it is no Hollywood version of what happened on that day. There is sparse use of music to try to pump up your emotions. The story is shown so matter of factly that you feel like you are watching a filmed version of the real events. There are no famous actors in the movie.
The film moves between basically four groups to tell its story: The people at air control, the military control center, the Arabs who took the plane, and the passengers.
The director is very effective at showing the cluster**** that resulted in communications between the people who made the decisions to handle the attack, their shock and their slow acceptance of the unbelievable, the passing of erroneous information which results in a catastrophic event of this magnitude. The Arab hijackers, at least to me, were victims also. Victims of a religion they were trained to hypnotize themselves with. In fact, the film opens with a black screen and you hear the chanting of their prayer as they ready themselves to begin their mission. And there is also the heroic bravery of the passengers who made a valiant attempt to take the plane back and charged the cockpit. They knew their chances were slim and they decided not to go quietly. They knew they had someone on the flight that was a pilot and could possibly fly the plane. They made a plan despite the hijackers screaming at them to sit down and be quiet, and then they made their move.
After you see this film you'll know what matters to you most in life.