Milsurp After Hours

.....posted on my local Photographic Club site.

Interesting colorization. Hand tinted postcards or something? Not a modern colorization with the flaws in the image surfaces showing. Here's what looks to be a photograph of a painting of a plane and crew somewhat like one you are showing. You can see some minor surface damage or dirt. Could this also be an actual photo that was painted over to begin with?

No, it was an early color photography process patented in 1903 by the Lumière brothers in France.

https://en.wikipedia.org/wiki/Autochrome_Lumi%C3%A8re

I wasn't paying close enough attention to the"Autochrome" in the certificate. I also was pretty oblivious of autochrome history and hadn't thought color images were made during WWI era. From the link, those images you posted must have been made on glass plates with the special autochrome color process. The link says film versions of autochrome didn't come around until the 1930's if I read it right.