A J-11B fighter jet attached to an aviation brigade of the air force under the PLA Northern Theater Command flies through a valley during a flight training exercise in early May, 2018. (Photos: eng.chinamil.com.cn) 

A J-11B fighter jet attached to an aviation brigade of the air force under the PLA Northern Theater Command flies through a valley during a flight training exercise in early May, 2018. 

A J-11B fighter jet attached to an aviation brigade of the air force under the PLA Northern Theater Command flies over farmland during a flight training exercise in early May, 2018. 

A J-11B fighter jet attached to an aviation brigade of the air force under the PLA Northern Theater Command flies over an undisclosed sea area at an extremely-low altitude during a flight training exercise in early May, 2018. 

A J-11B fighter jet attached to an aviation brigade of the air force under the PLA Northern Theater Command flies over an undisclosed sea area at an extremely-low altitude during a flight training exercise in early May, 2018.