Um, I feel like I should point out that the reason regular soldiers don't do much in Strike Witches is because they're not very useful against the Neuroi and it would kind of be a waste of life to send them out there to try and fight them all the time. Sometimes planes and ships act as support for the Witches but that's not very common because the Neuroi can take them out very quickly.

That said there were engineers and stuff, just not direct combat personnel hanging around all the time. People in charge of technology and stuff were still around.

A 'regular' war effort doesn't really work against the Neuroi, which is why the Witches are used like they are. They don't want to just get people killed.

Also, WWI and WWII did not happen at all in Strike Witches. There were no huge armies ready to kill each other because the circumstances in Strike Witches' world were very, very different. Everything you see in the show was developed to be anti-Neuroi, and even then it was only the Witches who proved to be effective against them. Any non-Witch effort to fight the Neuroi kind of goes terribly terribly wrong.

Um, just felt like I should point that out. ^^;