Which German company built the first aircraft to fly under turbojet power?

Heinkel Flugzeugwerke was a German aircraft manufacturing company founded by and named after Ernst Heinkel. It is noted for producing bomber aircraft for the Luftwaffe in World War II and for important contributions to high-speed flight, with the pioneering examples of a successful liquid-fueled rocket and a turbojet-powered aircraft in aviation history, with both Heinkel designs' first flights occurring shortly before the outbreak of World War II in Europe.

The Heinkel name was also behind pioneering work in jet engine and rocket development, and also the German aviation firm that attempted to popularize the use of retractable tricycle landing gear, a relative rarity in early WW II German airframe design. In 1939, flown by Erich Warsitz, the Heinkel He 176 and Heinkel He 178 became the first aircraft designs to fly under liquid-fuel rocket and turbojet power respectively.

Heinkel was the first to develop a jet fighter to prototype stage, the Heinkel He 280, the first Heinkel design to use and fly with retractable tricycle gear. In early 1942, the photographic interpretation unit at RAF Medmenham first saw evidence of the existence of the 280 in aerial reconnaissance photographs taken after a bombing raid on the Rostock factory. Thereafter, the Allies began intensive aerial reconnaissance intended to learn more about the German jet aircraft programme.