Definition: The air force is a branch of the armed forces in the United States that specializes in providing defense and security services to the military and civilian population of the United States. It was originally created by Congress during World War II as an auxiliary force for the military, but today it is a separate federal agency with its own policies, command structure, and fiscal year (FY) 2021 budget. The Air Force is composed of various branches and components that work together to protect the country. These include: the Strategic Air Forces Command, which coordinates air power and operations for U.S. defense, including missions like reconnaissance, surveillance, and theater bombing; the Air National Guard, which includes reserve forces for air defense and other military uses; the Air Force Reserve Component, composed of non-combatants trained in aviation to provide support for mission-critical roles within the Air Force; and the Air Force Test and Training Center (ATTC), which conducts testing and training exercises. The Air Force's main function is to defend the nation against aerial attacks from hostile nations, but it also provides support services such as intelligence gathering, reconnaissance, and tactical air defense. The Air Force has a wide range of missions, including strategic bombing, reconnaissance, surveillance, and other activities that can be directed at enemy military targets. The Air Force has been instrumental in various conflicts during the 20th century, including World War II, the Korean War, Vietnam War, and the Gulf War, among others. Today, the Air Force is a vital component of the U.S. armed forces and is responsible for maintaining national security through its air defense capabilities. The word "Air Force" can be defined as: - The branch of the armed forces in the United States that specializes in providing defense and security services to the military and civilian population. - A separate federal agency with its own policies, command structure, and fiscal year (FY) 2021 budget.