Funny how we tend to remember (and even look for ?) minor errors in otherwise entertaining films.
My personal “one to look for” in WWll era films is the presence of modern day “tram lines” in the cereal crops.
I guess you really need a farming background for it to be of noticeable significance (and probably be at least into your 60’s) but tram lines (the empty wheel marks for the tractor operator to follow every time he does tractor work in a cereal field) didn’t exist before the early 70’s. Before tram lines were brought into use you simply drove the tractor over the growing crop, as and when required. Now the same “un-cropped” tramlines are followed every time in the field . . . and so seeing tram lines continuously in the background / aerial shots in post 70’s films like Memphis Belle (with 1940’s binder cutter in a tram-lined wheat field behind the B-17 at Binbrook !) always brings a wry smile to my face.
And I’m smiling now as I think of you all thinking . . “tram lines in cereal fields? What is he going on about?”