American Airlines Flight 77 was involved in the September 11 attacks.
September 11 attacks . Two of the planes , American Airlines Flight 11 and United Airlines Flight 175 , were crashed into the North and South towers , respectively , of the World Trade Center complex in New York City . A third plane , American Airlines Flight 77 , was crashed into the Pentagon ( the headquarters of the United States Department of Defense ) in Arlington County , Virginia , leading to a partial collapse of the building 's western side .