U.S. Air Force Staff Sgt. Macer Allen, an air transportation specialist assigned to the 374th Logistics Readiness Squadron's combat mobility flight, rigs a low-cost, low-altitude airdrop bundle at Andersen Air Force Base, Guam, during the 62nd annual Operation Christmas Drop Dec. 9, 2013. Christmas Drop started in 1952 as a training mission and has since become the longest-running Department of Defense mission in full operation as well as the longest-running humanitarian airlift in the world.