Helicopter carriers have a similar appearance to other aircraft carriers but operate only helicopters – those that mainly operate helicopters but can also operate fixed-wing aircraft are known as STOVL carriers (see above). Seventeen are in service: four in Japan; three in France; two each in Australia, China, Egypt and South Korea; and one each in Brazil and Thailand. In the past, some conventional carriers were converted and these were called "commando carriers" by the Royal Navy. Some helicopter carriers, but not all, are classified as amphibious assault ships, tasked with landing and supporting ground forces on enemy territory. By size Fleet carrier Light aircraft carrier Escort carrier Supercarrier The appellation "supercarrier" is not an official designation with any national navy, but a term used predominantly by the media and typically when reporting on larger and more advanced carrier types. It is also used when comparing carriers of various sizes and capabilities, both current and past. It was first used by The New York Times in 1938, in an article about the Royal Navy's , that had a length of , a displacement of 22,000 tonnes and was designed to carry 72 aircraft. Since then, aircraft carriers have consistently grown in size, both in length and displacement, as well as improved capabilities; in defense, sensors, electronic warfare, propulsion, range, launch and recovery systems, number and types of aircraft carried and number of sorties flown per day. China, Russia, and the United Kingdom all have carriers in service or under construction with displacements ranging from 65,000 to 85,000 tonnes and lengths from to which have been described as "supercarriers". The largest "supercarriers" in service as of 2022, however, are with the US Navy, with displacements exceeding 100,000 tonnes, lengths of over , and capabilities that match or exceed that of any other class. Hull type identification symbols Several systems of identification symbol for aircraft carriers and related types of ship have been used. These include the pennant numbers used by the Royal Navy, Commonwealth countries, and Europe, along with the hull classification symbols used by the US and Canada. History Origins The 1903 advent of the heavier-than-air fixed-wing airplane with the Wright brothers' first flight at Kitty Hawk, North Carolina, was closely followed on 14 November 1910, by Eugene Burton Ely's first experimental take-off of a Curtiss Pusher airplane from the deck of a United States Navy ship, the cruiser anchored