United Kingdom military aircraft serial numbers are aircraft registration numbers used to identify individual military aircraft in the United Kingdom (UK). All UK military aircraft are allocated and display a unique registration number. A unified registration number system, maintained initially by the Air Ministry (AM), and its successor the Ministry of Defence (MoD), is used for aircraft operated by the Royal Air Force (RAF), Fleet Air Arm (FAA), and Army Air Corps (AAC). Military aircraft operated by government agencies and civilian contractors (for example QinetiQ) are also assigned registration numbers from this system.