well to put in the Air Force two cents...
the easiest way we teach recruits to remember the command structure of the Air Force is to memorise this saying: How many new airmen will get sore feet eventually? or
H = Headquarters Air Force - The Boss of Bosses. the air staff, and a whole bunch of other interesting things. Group That defines the Mission responsibility Currently responsible for the actions of 359,000 Active duty, 168,762 Civillian, and 230,830 Reserve personnel.
Major Command. These are the groups that specialise in acomplishment of a major mission, such as air defense, Strategic force, Logistics, personnel movement, and territorial defense. These are organizations like Air Combat Command, Air Mobility Command, et all, and can have up to 90,000 personnel.
Numbered Air Force: This is the level of command that are tactical echelons to provide operational leadership and supervision in the accomplishment of a mission. They support the following:
Air Division: this is an old administrative designator that comes and goes. Mostly used in wartime. 10,000 personnel
Wing - The highest command unit of the Air Force that can accomplish a mission by itself. Can be an Operational wing, Air base Wing (administrative) or Special Wing. composed of 1000 - 5000 personnel
Group - Usally two or more groups make a wing. At least a 1000 people.
Squadron - Basic unit of command in the Air Force that supports the accomplishment of a mission. Usally you have three or more squadrons to make a group. 100-300 personnel each.
Flight - Lowest level of operational organization that can accomplish a mission objective without outside support. 10-50 personnel.
Element - lowest group that can accomplish a mission objective in the Air Force. 1-10 personnel. This is the equivelant of a squad in the Army.
Notice how everything is wrapped around a mission? go to
www.af.mil and learn all about the Air Force Mission.