Air Transport Services Group (ATSG) is an American aviation holding company which provides air cargo transportation and related services to air carriers and other companies that outsource their air cargo lift requirements. ATSG subsidiaries include three cargo airlines with separate and distinct U.S. FAA Part 121 Air Carrier certificates. ATSG provides air cargo lift, aircraft leasing, aircraft maintenance services, airport ground services, fuel management, specialized transportation management, and air charter brokerage services.  Wikipedia