Soviet/Moscow airspace experiences in the 1970`s.
Flying regularly into Moscow, if on time, we were just 5 minutes behind a BEA Trident from London - & were always parked alongside each other. One day, about an hour after arriving, I heard the Trident call for "Startup Clearance" - I followed. "Standby" ATC said. After a delay of about 5 minutes we repeated our requests. "Standby" again. BEAline Captain said, "What is the reason for the delay?". Tower :- "The President (it was Brezhnev then) is in the air - no further takeoffs until he lands - in 4 and a half HOURS" !!!. We asked was he flying into Moscow ?. "He is flying somewhere over the Soviet Union - no more flying allowed until he lands !!". So both aircraft sat there with passengers aboard - not allowed to disembark them - & the whole airport stopped operating. Eventually we were given Startup Clearance ... four & a half HOURS later !! (The outside air temperature was minus 25 degrees centigrade with snow on the ground. The usual solitary military armed guard remained just ahead of our nose throughout