Issued on August 19, 1941, the 15-cent value was the third in the Transport Plane Series. Red brown in color, its primary purpose was to pay the fifteen-cents-per-half-ounce international airmail rate to Costa Rica, Panama, the Panama Canal Zone, and to parts of the Lesser Antilles in the West Indies. The latter included Trinidad and Tobago, the Leeward Islands, and the Windward Islands in the British West Indies. It also paid the all-airmail rate to Newfoundland, which was still a Crown Colony and not yet a part of Canada.
The 15-cent Transport found additional usage when the U.S. international airmail rates were reduced and simplified. Beginning in November 1946, it paid the new fifteen-cents-per-half-ounce rate to Europe.