which german company built the first aircraft to fly under turbojet power
Heinkel He 178 The Heinkel He 178 was the world's first aircraft to fly under turbojet power, and the first practical jet aircraft. It was a private venture by the German Heinkel company in accordance with director Ernst Heinkel's emphasis on developing technology for high-speed flight. It first flew on 27 August 1939, piloted by Erich Warsitz. This flight had been preceded by a short hop three days earlier.
Watt steam engine The Watt steam engine (alternatively known as the Boulton and Watt steam engine) was the first type of steam engine to make use of a separate condenser. It was a vacuum or "atmospheric" engine using steam at a pressure just above atmospheric to create a partial vacuum beneath the piston. The difference between atmospheric pressure above the piston and the partial vacuum below drove the piston down the cylinder. James Watt avoided the use of high pressure steam because of safety concerns.[1] Watt's design became synonymous with steam engines, due in no small part to his business partner, Matthew Boulton.