TLDR; It's the "mobile war room" and "doomsday" airplane for government in the event of nuclear war. Archive: https://archive.today/FLpwQ From the post: >>A Boeing E-4B plane in the skies could be an ominous signal of impending doom as the vessel is designed to be deployed ahead of a deadly nuclear attack. Nicknamed the 'doomsday plane' because of it's ability to survive a nuclear blast, America's fleet of E-4B planes are meant to protect the president and high-ranking government officials from an apocalyptic-level attack. President Donald Trump on Sunday warned that nuclear weapons are the greatest threat to humanity and said that a nuclear war 'could happen tomorrow'. Trump, who is in charge of the second-largest nuclear stockpile in the world, told Fox News' Sunday Morning Features that the use of 'monster' warheads may 'end the world', adding that the 'level of destruction is beyond anything you can imagine'. But the US Air Force has a fleet of $223million top-secret aircraft that will serve as a mobile war room for the president and his top officials in the case of a national emergency.