Jeff Duford is standing next to an A-10, one of the most beloved planes of all time. It's painted green, a clue that it was designed for a threat that has disappeared — it was built at the height of the Cold War.
"The reason why it's painted this way is because at that time, this airframe was expected to stop Soviet tanks from rolling through Germany," says Duford, curator of the National Museum of the U.S. Air Force in Dayton, Ohio.