 Lahm was assigned to the War Department General Staff (WDGS) as a staff member and later chief of the Organization Branch, Operation and Training Division (G-3) from August 25, 1920, to July 1, 1924.He was then Air Officer at the Ninth Corps Area at the Presidio of San Francisco, California.On July 2, 1926, the Air Service was renamed the Air Corps by act of Congress and authorized two additional brigadier general positions as assistant chiefs of Air Corps.