The SR-71 Blackbird was one of the greatest tools of espionage ever built. Flying at speeds of Mach 3, it could out-fly any enemy fighter or surface-to-air missile. In addition to its unmatched speed, the design of the aircraft made it nearly invisible to radar. In short, it was a technological marvel that gave the United States a decided advantage over the Soviet Union when it came to surveillance.
A key element in making sure the Blackbird could withstand the high temperatures reached during its flights was titanium. The only problem with this was that the only country to produce adequate amounts of titanium was the Soviet Union.The CIA set up several dummy corporations around the world to purchase the material and then ship it to the United States. While the Soviets undoubtedly resented the intrusion of SR-71 reconnaissance flights, they could — unbeknownst to them — take a small measure of pride and ownership in the source of their irritation. source