Interesting polar-projected map of the world showcasing the early development of international air travel, in this case by Trans World Airlines.
The map was probably produced around 1944 or 1945 when airlines and the bodies governing them started to look forward to the Post-War environment and contemplate what would be possible with new airline technology. Around this time, polar equidistant projects start to take over as the preferred method for illustrating global air routes.
One of the keys to dating the map is the inclusion of two round-the-world routes, the westward of which includes a stop in Paramushiro - a remote island off Kamchatka, which was captured by the U.S.S.R. in 1945 and annexed by the country in 1946. Plans were in place in 1944 for the inclusion of a stopover on the island, but with the commencement of the Cold War that route would not have made sense for long.
Interestingly, the map uses "Foreign economic areas" as a justification for the routes chosen. From 1945, TWA was flying these or similar routes with Lockheed Constellations.