The Boeing E-4B "Night Watch" aircraft, commonly known as the "Doomsday plane," is an essential element of the United States defense infrastructure.

Short description
The E-4B functions as the National Air Operations Center (NAOC). Its primary mission is to provide a highly secure mobile command post for the President, the Secretary of Defense, and the Joint Chiefs of Staff in the event of a national emergency, such as a nuclear war or the destruction of ground command centers. In addition to its military role, the aircraft provides support to the Federal Emergency Management Agency (FEMA) in disaster response.

Strategic importance
Continuity of government: Provides an opportunity for national leaders to lead the armed forces and coordinate the actions of the civilian population, even in the event of inoperable ground facilities.

Round-the-clock readiness: At least one of these aircraft is on constant alert 24 hours a day, 7 days a week, at selected bases around the world.

Support for the Minister of Defense: Regularly used to carry out global command and control tasks during the international trips of the Minister of Defense.