From NASA: "Two NASA T-38 training jets are seen as they fly over the Pentagon, Thursday, April 5, 2012 in Arlington, VA. NASA, in cooperation with the Federal Aviation Administration, conducted training and photographic flights over the DC metropolitan area. T-38 aircraft have been used for astronaut training for more than 30 years as they allow pilots and mission specialists to think quickly in changing situations, mental experiences the astronauts say are critical to practicing for the rigors of spaceflight."