US Air Force secretly tested Soviet fighters

US Air Force examined the plane's technical characteristics and its performance in a potential aerial battle against American fighters.
 
Similar evaluations were conducted in 1969 with the MiG-17 under the not-as-delightfully-named Have Drill and Have Ferry campaigns. Other MiG examinations took place later, but details of those programs have not been declassified.
 
US military simulated Soviet-style air defense at a secret base in Nevada, Area 51. The existence of Area 51 was confirmed by the CIA when the agency released declassified documents through a Freedom of Information Act request by George Washington University's National Security Archive. The initial documents show that Area 51 was used to test the US government's aerial programs.
 
Robert Singel, National Reconnaissance Office deputy director, said in a 1974 letter that releasing the photos to the public "would almost certainly provide strong stimulus for media questioning and the potential near-term revelation of the missions of the installation."
 
The site was eventually transferred from the CIA to the air force in the late-1970s and became widely known in the mid-1990s.