This map is originally from The People’s Atlas, produced by the London Geographical Institute.
One amusing aspect of this map is that hardly any these international air routes actually existed in 1920! The Atlantic wasn’t crossed by air until 1927.*** The Pacific was much later. Air routes in 1920 were more along the lines of London-Paris, or perhaps San Francisco-Los Angeles. So these are essentially “air routes of the future.”
I especially like the notation of how long it would take to get from London to any point on the map, if you were going 100 miles per hour. The images of the latest airplanes are also pretty cool.
UPDATE NOTE: ***A reader correctly points out:
“The first transatlantic flight had in fact occurred by the time of this map’s publication. The US Navy’s NC-4 flew across the Atlantic with a refueling in the Azores in May of 1919 It’s pictured above as the Curtiss Seaplane.. And see that R34 airship in the picture? That vessel made the trip a month later. While most of the transoceanic routes depicted were only notional in 1920, it’s not as if the Atlantic was some uncrossable barrier. In 1927, Lindbergh made the first solo non-stop flight, but plenty of other planes had made the journey before him.”