First Lieutenant Fleming was the pilot of a F-80C Shooting Star Fighter-Interceptor with the 25th Fighter-Interceptor Squadron, 51st Fighter-Interceptor Group. On 4 February 1951, while on a combat mission, during a rocket pass, his aircraft suffered an explosion, its wing fell off and it augured into the ground. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Fleming was awarded the Air Medal with Oak Leaf Cluster, the Purple Heart, the Korean Service Medal, the United Nations Service Medal, the National Defense Service Medal, the Korean Presidential Unit Citation and the Republic of Korea War Service Medal.