An aircraft type designator is a two-, three- or four-character alphanumeric code designating every aircraft type (and some sub-types) that may appear in flight planning. These codes are defined by both the International Civil Aviation Organization (ICAO) and the International Air Transport Association. ICAO codes are published in ICAO Document 8643 Aircraft Type Designators and are used by air traffic control and airline operations such as flight planning. While ICAO designators are used to distinguish between aircraft types and variants that have different performance characteristics affecting ATC, the codes do not differentiate between service characteristics (passenger and freight variants of the same type/series will have the same ICAO code). IATA codes are published in Appendix A of