The Lockheed Martin F-35 Lightning II (Lightning II) is a single-seat, single-engine, multi-role fighter built by Lockheed Martin as a fifth-generation aircraft to meet the needs of the USAAF, US Navy, US Army, and US Marine Corps. Initially designated the X-35 JSF, the designation was changed to F-35 Lightning II in 2006. Although the primary customer will be the US government, the project is also co-financed by other countries, particularly the United Kingdom, Italy, and the Netherlands. The main contractors are Lockheed Martin, Northrop Grumman, and BAE Systems.