Ding ding ding! We have a winner!
The Army is a military organization. The Navy, Marines, and Coast Guard(!) are naval organizations. Hence the name “US Naval Academy” and “US Coast Guard Academy”.
Air Force was created to not be a military organization, in order to be a more effective Air Force.
“ Hence the name, US Air Force Academy”.
Of course the Army had been running aviation with some degree of success since the Civil War. Thaddeus Lowe performed balloon reconnaissance during the Civil War, and performed the first overseas deployment in the Spanish American War. The Army air service observed the German preparations for the Marne offensive in WWI. The Army performed research on unmanned aircraft (The Kettering bug was an early attempt at a cruise missile) in the 1920s. The Army Air Force in WWII run the worlds largest air fleets.
Thanks for the explanation!