6 1 1 refers to Shenyang Aircraft Design Institute of China Aviation Industry Corporation I, which is an aircraft design institute established by People's Republic of China (PRC) and the state, and is the core unit of fighter design research in China. Cheng Fei, the full name of Chengfei Aircraft Manufacturing Co., Ltd., is a super-large enterprise directly under aviation industry corporation of china, an important subcontracting production enterprise and production base of fighter, foreign trade aircraft and civil aircraft parts in China, and an aviation research and production base. So it is best to choose 6 1 1.