The structure of the Air Force, like that of the Army, is based on a series of sub-unit and unit building blocks. The smallest sub-unit in the airforce is the section, several sections constitute a flight, several flights a squadron, several squadrons a wing, and several wings a group. Wings and groups are usually composed of squadrons with the same function, for instance several transport squadrons are grouped together to form a "transport" wing. Unlike the rigid structures of the Army, the Air Force's structures are inherently flexible and depend upon the role of any given unit or sub-unit. For example, a squadron with one task may have only two flights, while another squadron with a different role may have four or five. The number of personnel in any unit or sub-unit also varies widely depending upon the type of aircraft and equipment that unit or sub-unit operates. The table below outlines the rough structure of the Australian Flying Corps and the Royal Australian Air Force from 1916 to the present.

RAAF structure

Year
Flight
Squadron
Wing
Group
1916 RFC: 3 aeroplanes 3 Flights 2-6 Squadrons 2-6 Wings
AFC: 4 aeroplanes
1917 AFC: 6 aeroplanes 3 Flights 2-6 Squadrons 2-6 Wings
1943 Fighters and Bombers: 6 aircraft 2-4 Flights 2-6 Squadrons 2-6 wings
Transport: 6 aircraft
Maritime: 3 aircraft
1965 Bomber: 4 aircraft 2 Flights 2 Squadrons Flexible
Helicopter: 4 aircraft
Transport: 6 aircraft 3 Flights  
1998
Flexible

Air Force squadrons can be classified according to their role and the type of aircraft that they operate. The major types of air force squadrons are listed below.

Fighter
Fighter squadrons operate small, fast aircraft, usually only crewed by a single pilot, and their role is to protect larger, slower aircraft such as bombers and transports and also to seek out and destroy enemy aircraft.

Bomber or Strike
Bomber squadrons operate larger aircraft that are usually crewed by two or more people. Their role is to attack enemy targets on the ground and sometimes at sea by dropping bombs on them.

Transport or Airlift
Transport squadrons operate a range of aircraft of all sizes, including helicopters; their role is to transport personnel and equipment.

Maritime
Maritime Patrol squadrons are responsible for patrolling the sea to locate and attack enemy shipping and submarines. Maritime patrol aircraft are usually large and crewed by two or more people to allow them to patrol for hours on end. Their main weapons are rockets, missiles, depth charges and torpedoes.

Army Co-Operation
Army Co-Operation squadrons are tasked with supporting ground troops by attacking enemy troops, vehicles, equipment and fortifications. They usually operate small to medium size aircraft which are slower and more heavily armed than fighter aircraft.

Airfield Defence
Airfield Defence squadrons do not actually operate aircraft but are organised similar to an infantry company in the army, usually with heavier firepower, and are tasked with defending airfields from attack from ground forces.

Airfield Construction
Airfield Construction squadrons are another air force unit that does not operate aircraft. These squadrons are similar to army engineers and their task is to build and repair airfields.