Atlas Air Worldwide Holdings was formed in 2001, and is involved in the airport-to-airport air transportation of heavy-freight cargo through its two operating subsidiary airlines, Atlas Air and Polar Air Cargo. The company operates a fleet of more than 40 Boeing 747 aircrafts and provides four specific services types, including leasing, global scheduled service, commercial charter services and United States Military charter services. The core of Atlas business is the leasing of its freighter aircraft on an aircraft, crew, maintenance and insurance contract basis. Under an ACMI, or wet lease contract, customers receive a dedicated aircraft that is crewed, maintained and insured by Atlas in exchange for agreed-upon rates and level of operation. The company also acquired Polar, which provides all-cargo scheduled services throughout the world, from GE Capital Aviation Services Polar.