Context : Hans-Georg von Seidel (11 November 1891 -- 10 November 1955) was a German military leader who served in the German Army during World War I and in the Luftwaffe (German Air Force) during World War II. Seidel was promoted to the rank of General der Flieger (General of the Air). 
Answer : World War I
In which war did Hans-Georg von Seidel participate?