On January 21, 1919, Major Hickam was appointed chief of the Information Division, Office of the Director of Air Service, in Washington D.C., where he supervised the first written history of the Air Service. He reverted to his permanent rank of captain on 30 June 1920, received a promotion to major, Cavalry on 1 July, when the National Defense Act of 1920 took effect, and received a transfer to the Air Service in the grade of major on 6 August 1920.