Tonight the space shuttle landed at Edwards Air Force Base in California after being waved off two days in a row from Florida. This got me thinking about the 747 that carries the space shuttle. Wikipedia points out that there are two Shuttle Carrier Aircraft. Both were originally flown by airlines, the first by American Airlines, and the second by a Japanese airline. The engines had to be upgraded and all extra weight was stripped from the plane, but there are still a few seats left in the first class section in the front of the plane. There have only been these two and the first one was the one that launched the unpowered shuttle prototype Enterprise back in 1977. The shuttle has landed at Edwards 54 times.
One funny thing in the Wikipedia article is the following picture of one of the mounts on top of the 747 where the shuttle connects to the plane: