As the hijackers checked in at Dulles International Airport (Washington, D.C.) on the morning of September 11, 2001, Hani Hanjour was “flagged by CAPPS [Computer-Assisted Passenger Prescreening System], and the Hazmi brothers [Nawaf and Salem] were flagged by the American Airlines ticket agent because one of them had no photo identification and could not understand English, and because the agent found both to be suspicious. But…because Hanjour had only carry-on luggage, and no one was carrying any explosives anyway, the selection process proved useless.”
– James Bamford, The Shadow Factory, Pages 83-84