Complex sentence: He was assigned to the 186th Aero Squadron at Weißenthurm in May 1919, returned to the United States in July, and was discharged from the Army on 15 August 1919.
Split into simpler sentences: He was assigned to the 186th Aero Squadron at Weißenthurm in May 1919. He returned to the United States in July 1919 and was discharged from the Army on 15 August 1919.