USAF E-4B Advanced Airborne Command Post (AACP)
The Boeing E-4B serves as a survivable mobile command post for the National Command Authority, namely the President of the United States, the Secretary of Defense, and successors. The four E-4Bs are operated by the 1st Airborne Command and Control Squadron of the 595th Command and Control Group located at Offutt Air Force Base, near Omaha, Nebraska.
An E-4B when in action is denoted a "National Airborne Operations Center".
https://en.wikipedia.org/wiki/Boeing_E-4
at Lincoln Airport, NE on April 26 to commemorate the NAOC's 60th Anniversary
Video by Senior Airman Reilly McGuire
8th Air Force Public Affairs