A controller at Cleveland Air Route Traffic Control Center overhears this transmission from Flight 93: “Ladies and Gentlemen: Here the captain, please sit down keep remaining sitting. We have a bomb on board. So, sit.” The cockpit voice recording also indicates that a woman, most likely a flight attendant, is being held captive in the cockpit. Cleveland Center reports to the Herndon Command Center that the flight may have a bomb on board.1

1 9/11 Commission Report” National Commission on Terrorist Attacks Upon the United States 7/22/04. Web. March 17, 2011 page 39 http://www.9-11commission.gov/report/911Report.pdf