September 11 (9/11) Attacks
Federal Aviation Administration (FAA)
Orville Wright Federal Building, Washington D.C., U.S.
At 9:42 a.m., the Federal Aviation Administration (FAA) grounded all civilian aircraft within the continental U.S., and civilian aircraft already in flight were told to land immediately. All international civilian aircraft were either turned back or redirected to airports in Canada or Mexico, and were banned from landing on United States territory for three days.