Flight Lieutenant Flight Lieutenant ( Flt Lt in the RAF and IAF ; FLTLT in the RAAF and RNZAF , F / L in the former RCAF ) is a junior commissioned rank in the Royal Air Force and the air forces of many Commonwealth countries . It ranks above Flying Officer and immediately below Squadron Leader . The name of the rank is the complete phrase ; it is never shortened to " Lieutenant " . In informal usage , a flight lieutenant is sometimes referred to as a " flight lieuy " . It has a NATO ranking code of OF - 2 , and is equivalent to a Lieutenant in the Royal Navy or a Captain in the British Army or the Royal Marines . The equivalent rank in the Women ' s Auxiliary Air Force ( WAAF ) , Women ' s Royal Air Force ( WRAF ) ( until 1968 ) and Princess Mary ' s Royal Air Force Nursing Service ( PMRAFNS ) ( until 1980 ) was Flight Officer . Origins . On 1 April 1918 , the newly created RAF adopted its officer rank titles from the British Army , with Royal Naval Air Service Lieutenants ( titled Flight Lieutenants and Flight Commanders ) and Royal Flying Corps Captains becoming Captains in the RAF . In response to the proposal that the RAF should use its own rank titles , it was suggested that the RAF might use the Royal Navy ' s officer ranks , with the word " Air " inserted before the naval rank title . For example , the current rank of Flight Lieutenant would have been Air Lieutenant . Although the Admiralty objected to this simple modification of their rank titles , it was agreed that the RAF might base many of its officer rank titles on Navy officer ranks with differing pre - modifying terms . It was also suggested that RAF Captains might be titled as Flight - Leaders . However , the rank title Flight Lieutenant was chosen as Flights were typically commanded by RAF Captains and the term Flight Lieutenant had been used in the Royal Naval Air Service . The rank of Flight Lieutenant has been used continuously since 1 August 1919 . Usage . Although in the early years of the RAF a Flight Lieutenant commanded an aircraft flight , it is rare that a Flight Lieutenant is in command of a flying unit in the modern air force . However , ground flights which are administrative sub - divisions of squadrons are ordinarily commanded by Flight Lieutenants . In the Air Training Corps , a Flight Lieutenant is usually the Officer Commanding ( OC ) of a squadron . Insignia . The rank insignia consists of two narrow blue bands on slightly wider black bands . This is worn on both the lower sleeves of the tunic or on the shoulders of the flight suit or the casual uniform . The rank insignia on the mess uniform is similar to the naval pattern , being two band of gold running around each cuff but without the Royal Navy ' s loop . Unlike senior RAF officers , flight lieutenants are not entitled to fly a command flag under any circumstances . Other air forces . The rank of Flight Lieutenant is also used in a number of the air forces in the Commonwealth , including the Bangladesh Air Force , Ghana Air Force , Indian Air Force , Pakistan Air Force , Royal Australian Air Force and Royal New Zealand Air Force . It is also used in the Egyptian Air Force , Hellenic Air Force , Royal Air Force of Oman , Royal Thai Air Force and the Air Force of Zimbabwe . The Royal Canadian Air Force used the rank until 1968 , when the three armed services were unified and Army - type ranks were adopted ; Flight Lieutenants became Captains . In official French Canadian usage , a flight lieutenant ' s rank title was " capitaine d ' aviation " .