There were airplane battles during World War II, and fighter planes became a more important war instrument in this time. The Battle of Midway between American and Japanese forces included fighting in the air as a key component.
Most air-to-air combat was focused on machine guns attached to each plane, though there were some cannons and rockets that helped fight larger aircraft. This was also the era when bombers became commonly used in war, including the advent of nuclear weapons at the end of the war. Radar was another key technology used in planes, and aircraft was essential in providing support for ground troops.