To make the movie as authentic as possible, director
Paul Greengrass cast a number of real-life participants in the events of September 11, 2001, to play themselves. The principal "real-life role" in the movie is
Ben Sliney, the FAA's National Operations Manager, who made the decision on 9/11 to shut down all air traffic operations in the United States. Sliney had just been promoted to the National Operations Manager position, and September 11, 2001 was his first day on the job. That explains the applause from the FAA flight monitors when he walks into the control center in Herndon, VA, at the beginning of the movie. Several officials who were with Sliney in the FAA control room on 9/11 play themselves, including
Tobin Miller,
Rich Sullivan, and
Tony Smith. In the scenes at Newark Airport, several air traffic controllers who were in the Newark control tower on 9/11, and who witnessed the air attacks on the World Trade Center, play themselves. At the air traffic monitoring centers in Boston, New York, and Cleveland, the air traffic monitors are all played by real-life air traffic controllers, including several who were at these locations on 9/11, and who monitored the hijacked flights. At the Northeast Air Defense Command Center (NEADS) in Rome, NY, most of the military personnel are played by real-life military air traffic controllers, including several people, notably Major
James Fox, who were at NEADS on 9/11. Also, on United Flight 93, the actors playing the pilots in the movie are real-life airline pilots, and the flight attendants are played by real-life flight attendants, some of whom work for United Airlines.