Beginning with the July 1925 issue of the Postal Guide, a new section on Air Mail Service was added. As the domestic air mail service grew, maps illustrating the current air mail service routes were published at irregular times in the Postal Guide. The present document is a compilation of these maps as found in the various Annual and Monthly and Quarterly issues of the Postal Guide.

Shortly after this compilation was prepared, we received an e-mail from the USPS Historian, Jennifer Lynch, which included similar series of domestic air mail maps, which included some useful annotation about the changes reflected in those maps, plus several later maps which were published post-war in color for which we did not have a good image.