Combine the Army and the Air Force into one military service.

The Military Serves have so many dupicated efforts including intelligence, medical services, family support and the list goes on.
The Marines support the Navy and work for the Department of the Navy. This allows them to combine services and efforts. It also allows the to have the Training, Tactics and Proceedures.
The Air Force supports the Army. They move the troops, provide air support, airbreathing intelligence collection and the list goes on.
DOD has already started trying to save money by combining co-located bases, that the next step in these money / cost saving measures. Bring back the Army Air Corps / Army Air Force.