As US President Donald Trump mulls striking Iran's nuclear facilities, one of America's "doomsday planes" made a flight to Joint Base Andrews in Washington on Tuesday night. According to the New York Post, the E-4B Nightwatch - a plane designed to protect the Secretary of Defence and other national security officials and keep the government operating in the time of nuclear war - was spotted by flight trackers. The aircraft departed from Bossier City, Louisiana, on Tuesday evening and landed in Maryland around 4 hours later, after a long, winding route. What is a "doomsday plane"? A "doomsday plane" is...