The invasion of Poland in September of 1939, by Nazi Germany and soon after, Stalin’s Soviet Russia, was the start of what became known as the Second World War. (China and Japan had been fighting in 1937, and the attack on Pearl Harbor by Japan brought the USA into the war in 1941.)
This 1939 poster by W.T. Benda, was an example of the popular support for Poland that sadly was not translated into history-changing aid. It was from Polish War Relief, based in the USA, and entitled ‘Warriors of the Air’. (Some background to the poster and effort here.) The cavalryman has a symbolic set of the Polish hussar wings on his back, an icon with an aviation connection predating human flight by centuries, and used, as here as a Polish military symbol, including elsewhere in unit insignia. The aircraft is a bit of an oddity, as the artist, rather than using one of the many then-famous indigenous Polish aircraft types, seems to have based his work on the one off experimental high altitude research machine, the pressurised Lockheed XC-35. Maybe he thought this unarmed machine just looked more warlike than the real war machines. (You can see this image, below, flipped has been used as the main aeroplane.)
James Kightly, Vintage Aero Writer.
Image found in a number of online sources, including here.