The third Planes and Map airmail stamp was issued January 25, 1927, at Washington, D.C., and New York City. The format and design remained the same as the previous issues with a topographical map and two de Havilland DH-4 mail planes (see C7 and C8). This 20-cent stamp in yellow green paid the double-rate for one ounce for the new airmail rates effective February 1, 1927. The elimination of the complicated zone rate system allowed patrons to send a half-ounce letter across the country for only ten cents and also helped increase the use of the airmail service.
The de Havilland mail planes continued to fly although their manufacture was discontinued in 1926. Many were sold as surplus to barnstorming pilots, who flew them at county fairs and exhibitions, or transferred to other government departments. By December 31, 1927, the Post Office Department had eliminated most of its aviation material and equipment as private companies took over the airmail routes on contract.