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
Squadron leader Force (SLAF), Pakistan Air Force (PAF), Royal Australian Air Force (RAAF), Nigerian Air Force (NAF), and Royal New Zealand Air Force (RNZAF). It is also used in the Egyptian Air Force, Hellenic Air Force, Royal Air Force of Oman the Royal Thai Air Force and the Air Force of Zimbabwe The Royal Canadian Air Force (RCAF) used the rank until the unification of the Canadian Forces in 1968, when army-type rank titles were adopted. Canadian squadron leaders were retitled as majors. In official French Canadian usage, a squadron leader's rank title was "commandant d'aviation". The Chilean Air Force equivalent rank,