It is propelled by creating an ion wind using magnetohydrodynamics (MHD). MHD has been used to achieve vertical lift in the past, but only by cabling up the MHD ion generator system to an external power supply. History By May 2018 almost 100 electric aircraft were known to be under development. This was up from 70 the previous year and included 60% from startups, 32% from aerospace incumbents, half of them major OEMs and 8% from academic, government organizations and non-aerospace companies, mainly from Europe (45%) and the U.S. (40%). Mostly urban air taxis (50%) and general aviation aircraft (47%), a majority are battery-powered (73%), while some are hybrid-electric (31%), most of these being larger airliners. By May 2019, the number of known electric aircraft development programmes was closer to 170, with a majority of them aimed at the urban air taxi role. By 2022, about 100 electric aircraft designs were under development worldwide. By 2023, the number of sustainable aircraft concepts under development (not only electric) was estimated at up to 700. Airships The use of electricity for aircraft propulsion was first experimented with during the development of the airship in the latter part of the nineteenth century. On 8 October 1883, Gaston Tissandier flew the first electrically powered airship. The following year, Charles Renard and Arthur Krebs flew La France with a more powerful motor. Even with the lifting capacity of an airship, the heavy accumulators needed to store the electricity severely limited the speed and range of such early airships. Fully electric airships are expected to be available again by the 2030s. Unmanned aircraft In 1909, an electric free flight model was claimed to have been flown eight minutes, but this claim has been disputed by the builder of the first recorded electric Radio-Controlled model aircraft flight in 1957. Power density for electric flight was problematic even for small models. NASA's Pathfinder, Pathfinder Plus, Centurion, and Helios were a series of solar and fuel cell system–powered unmanned aerial vehicles (UAVs) developed by AeroVironment, Inc. from 1983 until 2003 under NASA's Environmental Research Aircraft and Sensor Technology program. On September 11, 1995, Pathfinder set an unofficial altitude record for solar-powered aircraft of during a 12-hour flight from NASA Dryden. After further modifications, the aircraft was moved to the U.S. Navy's Pacific Missile Range Facility (PMRF) on the Hawaiian island of Kauai. On July 7, 1997, Pathfinder raised the