The online version of the evening paper back in my hometown, the Albuquerque Tribune, had a great link to the Library of Congress. There is a collection of COLOR (and B&W) photos from the depression era through WWII on the home front. The great thing is you can put in search criteria for generally what you are looking for.
As a fun test I tried "aircraft" and was greeted with 80 color photos of various aircraft under construction or in various states of "undress." So you can get some good views, in color, of parts typically unavailable.
Good thumbnail (you do have to open this first from a list) and then can expand that one more time as either/or an uncompressed jpg/tiff image.
Hope this helps some others.