I cant find any information on Lt. Siebel in any of the reference books.
Willy Rosenstein states in his autobiography that Siebel took his place when Willy was shot down and wounded when he was in Jasta 19 during the Verdun Offensive, 1916. Willy states that Siebel distinguished himself in the further course of the war and later became a good friend of Göring. Siebel continued to fly in competitions and races after the war and later founded with Hanns Klemm an aircraft factory and then the Siebel Flugzeugwerke. Siebel helped Rosenstein to leave Germany by enlisting Görings help in 1936. Maybe I have looked in the wrong books? Any advice on Siebel's war record would be appreciated.
Lawrence Milner