Air Mail Postage Rates for U.S., Canada, and Newfoundland
Knowledge of postage rates can be very helpful in identifying how an air mail cover traveled. Two authors prepared the complete works for U.S. rates, including air mail rates; Henry W. Beecher and Anthony S. Wawrukiewicz. These books cover U.S. Domestic rates and U.S. International rates.
U.S. Domestic Postal Rates, 1872-1999, 2nd Ed. Henry W. Beecher and Anthony S. Wawrukiewicz, Cama Publishing Company, 1999.
U.S. International Postal Rates, 1872-1996, Henry W. Beecher and Anthony S. Wawrukiewicz, Cama Publishing Company, 1996.
In addition, Postal Digest Co. published a monthly guide known as the Official Foreign Air Mail Guide, that provided detailed listings of air mail service to the world from the U.S. and from the world to the U.S. This publication ran from 1940 through 1947. It started as a monthly and ended as a quarterly. The APRL has an issue for 1944. A complete collection is held at the New York Public Library. Issues can be obtained for a copy fee.
A summary of Canadian Air Mail Rates was included in the sixth edition of the American Air Mail Catalog series. That summary was expanded for the seventh edition, which at this writing is still in preparation. Also, an earlier summary of air mail rates for Newfoundland was revised.
The Air Mails of Canada and Newfoundland, 6th ed. American Airmail Society, 1997.
Canadian Air Mail Rates, Domestic and International 1925-2013, David Crotty,
Newfoundland Air Mail Postage 1937-1949, Jack Ince, and David Crotty
These two will be chapters for the volume 7th ed. Air Mails of Canada and Newfoundland
These two are currently available at the Aerophilately group: https://groups.io/g/Aerophilately/