I am not sure,what the English term for a double postcard is. Probably "Postcard with Reply". Here from Nepal such an item:
In the 1930s, 40s, & early 1950s, the ubiquitous 1c postal card, Sc. UX-27, served businesses of all kinds as the cheapest form of advertising -- just 1c, plus printing costs to take one's product directly to consumers. Here, from my stamp dealers cover collection, is a 1c postal card prepared and mailed by popular 1930s/40s Indianapolis, Indiana, cachet maker Harry Ioor announcing his latest cacheted first day covers. Don
From 1945 till 1972 the USA had occupied the Ryukyus. The northern groups were given back to Japan in 1953,the main-island Okinawa and the southern groups in 1972. I have several postcards,all mint or c.t.o.: New Year 1957
Our oldest daughter and her husband lived on Okinawa for three years and we were able to visit them a couple of times. Nice place, very low crime rates, excellent weather, but, yikes, they drive on the left side of the road there! I visited a stamp shop in downtown Naha on our second visit and made a purchase for my Aircraft on Stamps collection. The shop appeared to sell mostly new issues, but maybe if one knew the language there might have been other stamps available. Don
Don, you would not have much choice,looking for aircrafts on stamps from the Ryukyus.There are two only: The last of seven air-mail sets the Ryukyus have issued. Issued on Aug.28th,1963. It is remarkable,that amongst the 258 stamps,30 of them air-mails,only the above show airplanes. As far as stationery are concerned I am not sure,as I do not have the early (expensive) ones.