The Boeing X-32 was developed as a concept demonstrator aircraft for the Joint Strike Fighter competition after it merged with the Common Affordable Lightweight Fighter (CALF) program
The J-20 is a fifth-generation, twin-engine fighter designed by Chengdu. Early production aircraft are powered by Russian supplied AL-31FN Series 3 engines. Subsequent production configuration J-20As are powered by the AL-31 or derivatives of the WS-10 depending upon the production batch. Future aircraft may be powered by the WS-15.