 Although the remaining F-104As in regular USAF service had been recently fitted with more powerful and more reliable J79-GE-19 engines, the last USAF Starfighters left regular Air Force service in 1969.The aircraft continued in use with the Puerto Rico Air National Guard until 1975 when it was replaced by the A-7 Corsair II.The last use of the F-104 Starfighter in US markings was training pilots for the West German Air Force, with a wing of TF-104Gs and F-104Gs based at Luke Air Force Base, Arizona.