TUCSON, Ariz. -- It's nicknamed the Boneyard. It sits on 2,600 acres of desert land, with more than 3,000 military aircraft on the Air Force’s Davis-Monthan Base. It's more than a retirement home for planes from all four branches of the military, NASA, and the U.S. Forest Service. It's a sort of memorial with multiple uses. Many of the planes are scrapped for parts and some completely refurbished. The 309th Aerospace Maintenance and Regeneration Group (AMARG) is the only place in the country authorized to store military-grade planes. “We’re looked at as a national air power reservoir…How do you make...