A pair of asymmetrical electrodes under high voltage can produce an ionic wind and thrust. This phenomenon was discovered by Brown in the early 1920s and is known as Biefeld Brown effect. Electrical forces are able to accelerate ions in air and this has been proposed as an alternative method to today's standard propelling airplanes. The main advantages of the proposed full electric propulsion are: no moving parts, nearly silent in operation, and no combustion emissions. MIT realized the first flight of an airplane with solid-state propulsion based on ionic wind in 2018. The proof-of-concept airplane had a wingspan of 5 m and several free steady-level flights for more than 45 m and durations of about 10 seconds each were reported. A challenge for the future is to maximize the thrust-to-power ratio of ionic wind propulsion for electroaerodynamic airplanes. The experimental investigations carried out on different EAD thrusters with electrode gap distances of up to 80 mm showed a maximum thrust of 220 mN/m and a thrust-to-power ratio of 8.9 N/kW for a thrust of 100 mN/m.