In the 1960's, the Air Force developed a plane that could travel more than 3 times as fast as the sound produced by its own engines. The SR-71 Blackbird's incredible speed enabled it to gather intelligence in a matter of a few seconds while streaking across unfriendly skies. And in the off chance an enemy tried to shoot it down with a missile, all the Blackbird had to do was speed up and outrun it.