The Boeing 707 that President Ronald Reagan flew on first entered service in 1972 during Richard Nixon’s tenure as the 37th President of the United States. When the President was onboard the aircraft, it used the call sign Air Force One, and at other times, it used the call sign SAM Special Mission 27000 (spoken as “SAM two-seven-thousand.” The Boeing VC-137C, serial number 72-7000, served during the administrations of the following presidents: