Currently, the number of solo uses of the 50¢ sheet stamp on an international first-class air mail letter is: 9. 

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Description: There was a 50¢ per one-half ounce airmail rate to the Philippines in effect from 4/27/1937 until 12/11/1941. The Air mail letter from Johnson City, New York to the Philippines on December 23, 1939 pays that rate.

Owner/Source: Mike Ley

Images:

Description: There was a 50¢ per one-half ounce airmail rate to the Philippines in effect from 4/27/1937 until 12/11/1941. The Air mail letter from Johnson City, New York to the Philippines on December 23, 1939 pays that rate.

Owner/Source: Richard Pederson

Images:

Description: There was a 50¢ per one-half ounce FAM airmail rate From Hawaii to Europe in effect from 4/28/1939 until 10/31/1946. The Air mail letter from Hawaii to Scotland on December 7, 1940 pays that rate.

Owner/Source: Mike Ley

Images:

Description: There was a 25¢ per one-half ounce airmail rate to Asia, Australia, Oceania and Africa in effect from 11/1/1946 until 6/30/1971. The Air mail letter from an FPO to Shanghai, China on August 26, 1947 pays double that rate.

Owner/Source: Mike Ley

Images:

Description: There was a 50¢ per one-half ounce FAM airmail rate From Hawaii to all Pacific rim countries in effect from 5/23/1939 until 12/12/1941. The Air mail letter from Hawaii to Kowloon, Hong Kong on April 6, 1941 pays that rate.

Owner/Source: Mike Ley

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Description: There was a 50¢ per one-half ounce FAM airmail rate from New York to Curacao in effect from 12/1/1937 until 4/1/1945. The Air mail letter from New York City to Aruba on February 18, 1944 pays that rate.

Owner/Source: Mike Ley

Images:

Description: There was a 50¢ per one-half ounce Atlantic FAM airmail rate from the U.S. to and within India that was in effect from 5/23/1939 until 6/14/1940. The Air mail letter from New York City to Sydney, Australia mailed on March 16, 1951 pays double that rate for an up to one ounce letter.

Owner/Source: Richard Pederson

Images:

Description: There was a 25¢ per one-half ounce airmail rate from the U.S. to Australia that was in effect from 11/1/1946 until 4/30/1967. The Air mail letter from Albany, New York to Calcutta, India mailed on January 24, 1940 pays that rate.

Owner/Source: Mike Ley

Images:

Description: There was a 10¢ per one-half ounce airmail rate from the U.S. to the Bahamas that was in effect from 11/1/1946 until 7/1/1961. The Air mail letter from Miami, Florida to Nassau, Bahamas mailed on December 6, 1946 pays five times that rate for a letter up to 2½ ounces.

Owner/Source: Mike Ley

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