Combat aircraft from the Chinese People's Liberation Army fly in a two-plane formation in a valley at low altitude during an air actual combat training conducted on January 8, 2018. The two-plane formation is a main combat formation in air-to-ground combats. (Photos: 81.cn)

Combat aircraft from the Chinese People's Liberation Army fly in a two-plane formation in a valley at low altitude during an air actual combat training conducted on January 8, 2018. The two-plane formation is a main combat formation in air-to-ground combats.

Combat aircraft from the Chinese People's Liberation Army fly in a two-plane formation in a valley at low altitude during an air actual combat training conducted on January 8, 2018. The two-plane formation is a main combat formation in air-to-ground combats.

Combat aircraft from the Chinese People's Liberation Army fly in a two-plane formation in a valley at low altitude during an air actual combat training conducted on January 8, 2018. The two-plane formation is a main combat formation in air-to-ground combats.