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
East of Scotland Universities Air Squadron East of Scotland Universities Air Squadron The East of Scotland Universities Air Squadron (), commonly known as ESUAS, is a squadron within the Royal Air Force established in 2003 as an amalgamation of "East Lowlands Universities Air Squadron" (ELUAS) and "Aberdeen, Dundee and St Andrews Universities Air Squadron" (ADStAUAS). It is based at Leuchars Station (Royal Air Force Leuchars until 31 March 15 when it was transferred to Army control), in Fife and flies a fleet of 6 Grob Tutor aircraft. ESUAS is the parent Squadron of 12 Air Experience Flight, who share the aircraft. A Squadron Leader is the