1935-1937 China Clippers #C20-C22

1935-1937 Trans-Pacific Issues #C20-C22
To improve contact with its Pacific Island possessions, the U.S. inaugurated airmail service from San Francisco to the islands of Hawaii, Midway, Wake, Guam and the Philippines. Mail was flown by Pan-American Airways aboard large seaplanes known as China Clippers, named for the 19th century ships that carried tea back to the U.S. from the Orient.