On August 14, 1937, the Japanese invasion of China that started July 7, 1937, at the Marco Polo Bridge Incident, saw the first air to air combat of the 2nd Sino-Japanese War and arguably the first air to air combat of World War II (presuming you consider the start of the war between Japan and China as the start of World War II). While Japanese aviation and aviators are often given accolades as the best trained and equipped air forces in the Pacific theater early in World War II, this first aerial combat resulted in a resounding victory for the Chinese aviators.
Digging Deeper
Equipped with quaint, and already obsolete fighters despite only being in service a few years, the Chinese fighter pilots were flying American bi-plane fighters, the Curtiss F11C Goshawk (Hawk II), introduced in 1932 and the Curtiss BF2C Goshawk (Hawk III), introduced in 1933. Despite the later model being the most common Chinese fighter at the time, its performance was already laughable by European standards.
