I don’t think it used any at all and there’s no way the military would have let them in the sixties either. It was pretty much all stock footage.
Well, maybe you would want to use some military equipment to shoot scenes in the camp, or the cockpit stuff. But again, you didn’t need to, and as you said I’m pretty sure the military didn’t let them do it back on the 60s either, so…
It’s a moot point. However you can just shoot that stuff in countries that have American military gear.
What I’m saying is that you don’t really have to use any military gear at all, it’s not hard to make a couple of sets, the movies that need military gear are the massive war movies which take place primarily on warships etc.