Just an excuse to have a chopper in WW1?

I saw this movie as a child in the 80's and loved it, still like it and now I saw it again after 25 years on Blu Ray but with adult eyes and intelligent and it made me wonder what the point was with this movie.
I can't see any other reason that the makers of the film wanted to put a nice chopper in WW1 and made a story that could make that happend.
If there was more about time travel we would see more of those questions that would appear instead of just acception and finaly the chopper saves the day.

Fiona Hutchinson is hot though.