The Chengdu J-20, also known as Weilong, is a twin-engine all-weather stealth fighter developed by China's Chengdu Aircraft Corporation for the People's Liberation Army Air Force. The J-20 is designed as an air superiority fighter with precision strike capability. The aircraft has three notable variants: the initial production model, the revised airframe variant with new engines and thrust-vectoring control, and the aircraft-teaming capable twin-seat variant. Descending from the J-XX program of the 1990s, the aircraft made its maiden flight on 11 January 2011, and was officially revealed at the 2016 China International Aviation & Aerospace Exhibition. The aircraft entered service in March 2017 with the first J-20 combat unit formed in February 2018, making China the second country in the world to field an operational stealth aircraft.