Hans Klein Dipl . - Ing . Hans Klein ( 17 January 1891 – 18 November 1944 ) was a German World War I fighter ace credited with 22 aerial victories . During World War II he held the position of Geschwaderkommodore of the JG 53 " Pik As " fighter " Geschwader " ( wing ) . Early life and infantry service . Hans Klein was born in Stettin , when it was still within the Kingdom of Prussia and the German Empire ; today , Stettin is part of Poland because of changing national boundaries . Klein ' s birth date was 17 January 1891 . When World War I broke out in 1914 , Klein joined the Imperial German Army . He served first with the 34th Infantry Regiment , then with the 210th Reserve Infantry Division on the Western Front , beginning in October 1914 . He was commissioned as an officer in March 1915 . World War I aerial service . Hans Klein transferred to aviation service in March 1916 . He first flew with " Flieger - Abteilung " ( Artillerie ) : Flier Detachment ( Artillery ) 5 and " Flieger - Abteilung " ( Artillerie ) 6 on artillery ranging and reconnaissance duties . He then served in an early ad hoc fighter unit , a " Kampfeinsitzerkommando " ( Combat Single - Seater Command ) , claiming a 20 August 1916 aerial victory that could not be confirmed . Klein was then posted to a fighter squadron , " Jagdstaffel 4 " , on 4 November 1916 . He was credited with his first confirmed aerial victory on 4 April 1917 ; by the time Bloody April ended , his tally was up to eight , including an observation balloon on the 7th and a pioneering night - time victory on the 8th . He scored his ninth victory on 6 May 1917 ; three days later , he was wounded in action . Klein scored his tenth victory on 16 June 1917 , and once again began to notch victories . On 11 July , he managed to shoot down two enemy balloons in two minutes for his 15th and 16th victories . He was wounded again on 13 July 1917 , in combat versus Nieuport 17 s of No . 29 Squadron RFC . On 27 September 1917 , Klein assumed command of " Jagdstaffel 10 " . He began to score again on 2 October . He had already been awarded both classes of the Iron Cross and the Knight ' s Cross of the House Order of Hohenzollern . Now he qualified for the " Pour le Merite " with his 20th confirmed victory , scored on 18 October 1917 . He would score two more victories in late November , before he was awarded the " Pour Le Merite " on 2 December 1917 . Although he would not score again , he continued to fly until he was wounded again on 19 February 1918 . He lost a digit to a British bullet fired by one of the Sopwith Camel s of No . 54 Squadron RFC . Various sources say he lost either his right index finger or his thumb . Upon recovering , he served on ground duties with " Jasta 10 " on ground duties from 26 April 1918 until the end of the war . Post World War I . After attaining an engineering degree , in 1935 Klein joined the Luftwaffe as a Major , commanding JG 133 and JG 53 in late 1939 . He later served as Deputy Commander of all fighter schools and attained the rank of Major General before his retirement in April 1943 . He died on 18 November 1944 . The official cause of death was from injuries received in a car accident , however his family suspected he was murdered , an inspection of Klein ' s body allegedly showing evidence of a gunshot wound to the head .