U.S. Air Force Tech Sgt. Pablo Herrera, a loadmaster with the 36th Airlift Squadron, conducts preflight checks on a C-130 Hercules aircraft at Andersen Air Force Base, Guam, during the 62nd annual Operation Christmas Drop Dec. 11, 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.