Most of the good ones that are based on real actions have already been mentioned.
For a few fictional flicks that can be somewhat far fetched but just plain fun to watch:
- Where Eagles Dare (a personal favorite, far fetched or not)
- Kelly's Heroes (no negative vibes!

)
- Objective Burma
- Ambush Bay
- The Eagle Has Landed
These are films in a WWII setting that don't represent anything that actually happened; however, as I said, they are just plain fun to watch, far fetched or not.