The United States Air Force has two civilian components: Air National Guard and Air Force Reserve. It could be quite confusing as they both aid in the national defense of different military operations, and both are comprised of Citizen Airmen, too. The two, however, have several differences.
Air National Guard
The Air National Guard, also called Air Guard, is a separate federal reserve force of the United States Air Force. It is under the joint bureau of the Department of the Army and the Department of the Air Force, the National Guard Bureau. What’s interesting about the Air National Guard is that it is both a federal and state force. If it is under the Federal Force as per the President of the United States’ order, it becomes an active part of the United States Air Force. Now, if it is under the state jurisdiction, they report to the Governor and act as a militia force, usually during national or state emergencies like floods, hurricanes, or earthquakes.
Air Guard can be traced back to December 13, 1636, when the need to establish militia regiments arose. Bay Colony had to be defended against American Indians and other European countries in North America. As a result, the Massachusetts Bay Colony’s General Court passed an act calling to create three regiments and organize existing separate militia companies in and around Boston. This organization would later become the Army National Guard.
Militias were seen as territorial compared to, say, the naval forces, which were governed by federal laws and policies. This explains why the US Navy, US Marine Corps, and US Coast Guard do not have National Guard components. So why does US Air Force have a separate Air National Guard? The branch evolved from the US Army, so the former components of the US Army Air Forces were carried over, too, when it became the US Air Force in 1947.