The X-31 flight test program was conducted by an international test organization (ITO) managed by the Advanced Research Projects Office (ARPA), known as the Defense Advanced Research Projects Office (DARPA) before March 1993. The ITO included the U.S. Navy and U.S. Air Force, Rockwell Aerospace, the Federal Republic of Germany, Daimler-Benz (formerly Messerschmitt-Bolkow-Blohm and Deutsche Aerospace), and NASA. Gary Trippensee was the ITO director and NASA Project Manager. Pilots came from participating organizations.
The X-31 program demonstrated the value of using thrust vectoring (directing engine exhaust flow) coupled
with advanced flight control systems, to provide controlled flight to very high angles of attack. The result was a significant
advantage over conventional fighters in a close-in combat situation.