Army, Soldier Navy, Sailor Air Force, Airman Marine, Marine
It isn't. The Royal Air Force is an idependent force like the Royal Navy and the Army. The navy and army have their own individual air arms, the Fleet Air Arm and the Army Air Corps but each has individual roles.
As I understand the US Military system the heads of Army, Navy, and Air Force are appointed by the Secretary of Army, Secretary of Navy and Secretary of Air Force.
Five -United States Army (includes Army Reserve and Army National Guard)United States Air Force (includes Air Force Reserve and Air National Guard)United States Navy (includes Navy Reserve)United States Marine Corps (includes Marine Corps Reserve)United States Coast Guard (includes Coast Guard Reserve)
Lemay
Navy, Army & Air Force Institutes
They protect the country
Army, Air Force and Marines
With Japan's industrial base; Japan built a navy, army, and air force. After building those forces; their navy, army, and air force trained for war.
The 5 branches of the military - Coast Guard, Army, Navy, Air Force, and Marine Corps.
As I understand the US Military system the heads of Army, Navy, and Air Force are appointed by the Secretary of Army, Secretary of Navy and Secretary of Air Force.
Lemay