This Boeing 747-100 started life in September 1970 with American Airlines as N9668. In July 1974 it was sold to NASA were it remains in service today. NASA removed the American Airlines logo from the tail along with the N number and main titles. NASA retained the red, white and blue side stripes. The large side American logo was stripped and the metal was buffed clean. The location of the American Airlines titles was still visible after being stripped. By December 1974, 905 had the shuttle mounts added along with the new vertical fins on the stabilizers for the first SCA flight with the non-operational shuttle “Enterprise. ” This later version of 905 is the most unique with the added fuselage doublers and the mission markings denoting the flights.