 Maitland was transferred to Luke Field, Hawaii, and assigned to the 6th Aero Squadron on May 13, 1919.He petitioned to remain in the Army, passed the required examinations, and received a regular commission as a 1st lieutenant in the Air Service on July 1, 1920, the date that the service was recognized by law as an organizational part of the Army.Leaving Hawaii in May 1921, Maitland became an aide to General Billy Mitchell in July and was selected as one of the pilots to take part in the sinking of the battleship "Ostfriesland", a military experiment set up by Mitchell to prove the effectiveness of air power against ships.