Space shuttle Discovery makes final flight

The Space Shuttle Discovery, mounted on the Shuttle Carrier Aircraft, flies over Ronald Reagan Washington National Airport,in Washington, Tuesday, April 17, 2012. Discovery is en route from Kennedy Space Center to the Smithsonian National Air and Space Museum Udvar/Hazy Center at Dulles International Airport. The oldest surviving shuttle, Discovery holds the all-time record with 39 missions, 148 million miles, 5,830 orbits of Earth, and 365 days spent in space. All that was achieved in under 27 years. (AP Photo/NASA, Bill Ingalls)