Being a Subsidiary of Another Military Organization

Hey all, so I've been reading up on the military and everything.. and I came across a concept that I didn't quite get. What does it mean for a military branch to function as a subsidiary of another? Also, could you give me some examples? Thanks in advance!

Hello! Being a subsidiary of another military branch essentially means that the "subsidiary" branch operates under the larger "parent" branch. Typically, this happens when a new need arises that is outside the scope of existing branches, and a new branch is created to specifically address that need. However, since the new branch often shares many similarities or responsibilities with an existing branch, it's placed under that existing branch's jurisdiction to maintain coordination and effectiveness.

One prime example of this structure in U.S. history is the relationship between the U.S. Air Force and the U.S. Army. The Air Force didn't always exist as a separate branch; instead, it started as the Aeronautical Division under the U.S. Army Signal Corps in 1907. Over time, as military aviation developed and its importance grew, the Aeronautical Division morphed into the Army Air Forces during World War II. However, it was still part of the Army and operated under Army command. It wasn't until 1947 that the U.S. Air Force became a separate and co-equal branch of the military.

Another example could be the U.S. Space Force, which was established in 2019. As of now, the Space Force functions as a subsidiary of the U.S. Air Force. It's officially a separate branch, but the Department of the Air Force oversees it.

Note that despite being "subsidiary", these branches still hold considerable autonomy and specialized roles. They're organized under a parent branch mainly for administrative and logistical needs.