Security Control of Air Traffic and Air Navigation Aids
The Plan for the Security Control of Air Traffic and Air Navigation Aids (SCATANA) is an emergency preparedness plan of the United States which prescribes the joint action to be taken by appropriate elements of the Department of Defense, Federal Aviation Administration, and the Federal Communications Commission in the interest of national security in order to effectively control air traffic and air navigation aids under emergency conditions. Known versions of the plan are dated June 1971 and August 1975. The plan implements parts of the Federal Aviation Act of 1958, the Communications Act of 1934, and Executive Order 11490 of October 28, 1969 (amended by Executive Order 11921 on June 11, 1976).
Use on September 11, 2001
The U.S. plan has been implemented once (other than tests) since its inception, and even then, it was a modified version. On September 11, 2001, the codeword was broadcast ordering that all U.S. air traffic be grounded, after the September 11 attacks. Even in that instance, the emergency plan was only partially implemented as the Defense Department left command and control of the air traffic system with the FAA and intentionally allowed all radio navigational aids to remain in operation to aid in the process of controlling and landing the thousands of planes which were aloft in domestic airspace.
While several people have been credited with issuing the SCATANA order for a national ground stop, the 9/11 Commission credits FAA National Operations Manager Ben Sliney with effectively issuing the directive. At 9:42 am on the morning of September 11, 2001, after the Air Traffic Control System Command Center learned from news reports that a plane (American Airlines Flight 77) had crashed into the Pentagon, Sliney "ordered all FAA facilities to instruct all aircraft to land at the nearest airport." 
Canada rolled out Operation Yellow Ribbon to handle the diversion of most international civilian airline flights that were bound for the United States to place these aircraft on the ground in Canada. In total, 255 aircraft were diverted to 17 different airports across Canada. Some international civilian airline flights bound for the United States were instead diverted to other countries (including Mexico) or canceled outright.
Military exercises known as Operation Skyshield had temporarily closed U.S. airspace to civilian traffic in the early 1960s.
- United States Air Force, United States Army, United States Navy (25 June 1976). "Security Control Of Air Traffic And Air Navigation Aids (SCATANA)" (PDF). Archived from the original (PDF) on March 12, 2009. Retrieved May 18, 2009.
- "§5-6-1-g Special Security Instructions". Aeronautical Information Manual. Federal Aviation Administration. Archived from the original on 2009-08-01.
- Canada Gazette (October 9, 2002). "Regulations Amending the Canadian Aviation Regulations (Parts I, VI and VIII)". Retrieved May 18, 2009.
- "Leader Focus — SCATANA". November 18, 2001.
- Eberhart, General Ralph (June 17, 2004). "Transcript: 9/11 Commission". The Washington Post.
So our SCATANA said, "Leave the nav aids on." Our SCATANA said, "FAA, you still control the traffic that's flying." Our SCATANA said, "Law enforcement and Flight For Life can continue to fly." We don't want to ground them during this terrible tragedy. And then procedures for getting waivers to fly. So we had to take that procedure and modify it to this horrific act that occurred on 9/11.
- 9/11 Commission Report