Commander Air Force's mid-rank officers' ranks are modelled on those of the Royal Navy, the term wing commander is used as a rank, and this is the equivalent of a lieutenant colonel in the army or a commander in the navy. The rank of wing commander is above that of squadron leader and below that of group captain. In the former Royal Naval Air Service, which was merged with the Royal Flying Corps to form the Royal Air Force in 1918, the pilots held appointments as well as their normal ranks in the Royal Navy, and they wore insignia appropriate to
Marshal of the Royal Air Force (marshal of the Royal Air Force is equivalent to a five-star rank) on an air force blue background. The rank insignia and flag exists in some other air forces for equivalent ranks. The rank title differs slightly, often being a variation on marshal of the air force, usually with the name of the relevant air force in place of the words 'Royal Air Force'. A notable example of this practice is the rank of marshal of the Royal Australian Air Force. Unlike other MRAFs who only relinquished their appointments, Sir Peter Harding resigned from the RAF in 1994. Consequently, his