The United States Air Force E-4B Nightwatch, better known as the Doomsday planes, may not get as much attention as the Presidential Air Force One aircraft, but they are kept in a high state of readiness. The four Air Force E-4B Nightwatch aircraft are part of the United States’ strategy to keep the highest level of government functioning even in the event of a nuclear attack (or another emergency). There are many things to know about the secretive E-4B Nightwatch aircraft and how they are intended for a worst-case scenario.