The first United States Air Force officer to earn the distinction of rated pilot, he served during the World War II era as a member of the U.S. Army Air Corps. His military honors include the Distinguished Service Medal, the Legion of Merit, and the French Legion d'Honneur.
He graduated from the United States Military Academy in 1909 and received his first commission as a Cavalry second lieutenant.
He belonged to a distinguished group of pilots known as the Early Birds of Aviation.
The son of Ida Roberts Milling and Judge Robert Milling, he spent his childhood in Winnfield and Franklin, Louisiana.
In the mid twentieth century, Milling and U.S. Army officer Lucius Clay both attained the military rank of Brigadier General.