I was really impressed that so many people played themselves. We find this out in the credits at the end: Many of the FAA and military were the actual people on the job during 9/11.
In retrospect, I think the movie shouldn't have had music. The music was fine, but contrasted with much of the documentary aspects of the movie.
I don't know if it's capital-I Important, but United 93 presents one piece of a large picture with which we are still grappling.
