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 NATO ranking code of OF-3, equivalent to a lieutenant-commander in the Royal Navy or a major in the British Army or the Royal Marines. The equivalent rank in the Women's Auxiliary Air Force, Women's Royal Air Force (until 1968) and Princess Mary's Royal Air Force Nursing Service (until 1980) was "squadron officer". Squadron leader has also been used as a cavalry command appointment (UK) and rank (France) since at least the nineteenth century. In Argentina it is used as a command appointment by both the army's cavalry and by the air force's flying units. The cavalry rank of squadron leader