In the past two years, the U.S. Air Force retired 252 elderly A-10s, F-15s and F-16s to the "bone yard" (a desert storage areas where many American warplanes are stored when retired, just in case they are needed later.) Sometimes the air force is just saving money, by mothballing and decommissioning a number of active duty airplanes to free up money for upgrades and maintenance on the rest of the fleet. Thus not all the aircraft in the bone yard are old and worn out. In fact, nearly all aircraft sent to the bone yard can fly again, otherwise they...