A fighter aircraft attached to an aviation brigade of the air force under the PLA Northern Theater Command zips through a valley in a combat sortie. (Photos: eng.chinamil.com.cn)

A fighter aircraft attached to an aviation brigade of the air force under the PLA Northern Theater Command zips through a valley in a combat sortie.

A fighter aircraft attached to an aviation brigade of the air force under the PLA Northern Theater Command zips through a valley in a combat sortie.

A fighter aircraft attached to an aviation brigade of the air force under the PLA Northern Theater Command zips through a valley in a combat sortie.

A fighter aircraft attached to an aviation brigade of the air force under the PLA Northern Theater Command zips through a valley in a combat sortie.

A fighter aircraft attached to an aviation brigade of the air force under the PLA Northern Theater Command zips through a valley in a combat sortie.