The Gloster E.28/39 was the first British jet powered aircraft that was used during World War II. The first of two examples, with serial number W4041/G, was initially flown on 15th May 1941 by Garry Sayer, two years after the first flight of the German Heinkel He 178, which was the first jet aircraft ever made. The aircraft was able to reach speeds of up to 544 km/h.