Ronald Reagan Washington National Airport tower passes to the Secret Service Operations Center in Washington the alarming word that “an aircraft is coming at you and not talking with us.” A minute later, Flight 77 turns south below Alexandria, Virginia, circles back to the northeast, and flies toward Washington again. The destination is the Pentagon, not the White House or the Capitol.1

1 Goldberg, A. Papadopoulous, S., et al "Pentagon 9/11" Historical Office, Office of the Secretary of Defense n.d PDF. March 16, 2011 page 25 http://osdhistory.defense.gov/docs/Pentagon%209-11.pdf