I think Battle of Britain is a decent film and it has good flying in it but I think its over rated by a lot of people. Its flaw is that it trys to take too broad an approach: its got about 20 main characters , you dont know whose where, what they're doing and it never stays on anyone for more than a few minutes. This is seen in many 50/60s war films. I think it would be better if they had one main character at one squadron rather trying to show everything.
Another example of this would be the Longest Day: it shows you the whole invasion on all the beaches and has generals for main characters. I think its better when its someone's expierience of the battle rather than a film about the battle itself.