When the Army was reorganized by Congress on June 4, 1920, the Air Service was recognized as a combatant arm of the line, third in size behind the Infantry and Artillery. On July 1, 1920, Mitchell was promoted to the Regular Army (i.e., permanent) rank of colonel in the Signal Corps, but also received a recess appointment (as did Menoher) on July 16 to become Assistant Chief of Air Service with the rank of brigadier general. On July 30, 1920, he was transferred and promoted to the permanent rank of colonel, Air Service, with date of rank from July 1, placing him first in seniority among all Air Service branch officers. On March 4, 1921, Mitchell was appointed Assistant Chief of Air Service by new President Warren G. Harding with consent of the Senate. On April 27, Mitchell was reappointed as a brigadier general with date of rank retroactive to July 2, 1920.