The Eleven-cent Prexie
International air-surface-air use
The rate for a letter that was transported by air in the United States to a distribution point, then sent by surface transportation to Europe before being sent by air to its final destination in Europe was eleven cents for the first half ounce from November 23, 1934 until October 1, 1946.
This cover, sent to Holland in 1939, specifies air mail, "to boat and in Europe."
The same combination of rates applied to mail originating in the Territory of Alaska as well.
This cover was sent from Alaska to Sweden in 1940.