On the morning of September 11 , 2001 , a duty officer from the 113th Wing , D.C. Air National Guard , received a call from the U.S. Secret Service with instructions from the White House to get the F-16s in the air . The Pentagon had just been hit , and the White House knew another airliner , United Flight 93 — had been hijacked . After a call with the White House operations center , the 113th Wing commander issued a scrambled order to set up a combat air patrol over D.C. and to deter all aircraft within 20 miles with " whatever force is necessary … to keep from hitting a building downtown . " As the F-16 crew returned due to fuel , the next crew went out . There was no time to arm them with missiles , so each fighter went out carrying only 500 training bullets — just enough for a five-second burst . At the time , they believed that there may be more hostile aircraft . Each committed to doing whatever necessary to stop any hostile aircraft they encountered , up to and including ramming the airliner . By this point , fighters from Langley Air Force Base and the fighters from the D.C. National Guard were put in contact with each other . Flight 93 was no longer a threat , but the two units worked together to escort aircraft out of the airspace
United Flight 93
United Airlines Flight 93
District of Columbia National Guard