thumb|Gerhard Fieseler performing an upside-down flight in a Fieseler F2 Tiger
Gerhard Fieseler (15 April 1896 – 1 September 1987) was a German World War I flying ace, aerobatics champion, and aircraft designer and manufacturer.
From birth to the 1918 armistice
Born in Glesch (near Cologne), Fieseler joined the Air Service of the Imperial German Army in 1915. A crash during training hospitalized him until February 1916, but he had become an observation pilot by October 1916, flying first with Feldflieger Abteilung 243, then with Feldflieger Abteilung 41. In 1917 he qualified as a fighter pilot and was posted on 12 July to the Macedonian front, initially flying a Roland D.II with Jagdstaffel 25. Fieseler scored his first aerial victory on 20 August 1917. A serious illness removed him from active duty from 21 September until 5 November 1917.
Fieseler would not score his second success until 30 January 1918. He was eventually credited with nineteen confirmed aerial victories, with three others unconfirmed. Commissioned in October 1918, he was the highest-scoring German ace on the Eastern Front to survive World War I. He was awarded the Golden Military Merit Cross and the Iron Cross, first and second class.