Milch enlisted in the German Army in 1910, where he rose to the rank of lieutenant and commanded an artillery unit in East Prussia on the outbreak of WW1. He saw action against the Russian Army on the River Deime in September 1914 and later on the Angerapp Line in February 1915. In July 1915, he was transferred to the Luftstreitkräfte (Imperial Air Force) and trained as an aerial observer on the Western front, seeing action on the Somme 1916 and later in Flanders 1917. After a spell as a company commander in the trenches in the spring and summer of 1918, in the waning days of the war, he was promoted to captain and appointed to command a fighter wing, "Jagdgruppe 6", even though he had never trained as a pilot and could not fly himself.