The "Battle of Britain" was one of the most critical battles of World War II, and was fought against Germany by the RAF. The German Luftwaffe planes way outnumbered what the RAF had -- something like 640 vs. 2500 - astonishing - but the RAF went ahead anyway to keep Germany from invading their country.
I'm not a World War II expert, though I'm sure there are plenty of them who have seen this film and posted a review, so I'll leave the critiques about whether or not this was a realistically told story to them.
In my own opinion, it was a lot of stars without much to do and some fantastic aerial battles. The stars include Michael Caine, Trevor Howard (replacing Rex Harrison), Harry Andrews, Laurence Olivier, Ralph Richardson, Christopher Plummer, Ian McShane, Curt Jergens, Kenneth More, Nigel Patrick, Michael Redgrave, Robert Shaw, Susannah York, Robert Flemyng, and Edward Fox. Dirk Bogarde must have been on vacation. Timothy Dalton auditioned for a role but did not get it; Alec Guinness was to play a role that was eventually cut from the script. An astonishing cast.
Characters therefore weren't fully developed - there were so many of them - but the real story is in the skies where the battles rage, with some very exciting flight sequences as well as some glorious scenery. Filming took place in England and Spain.
For some history of the film, I suggest the "trivia" section here, which goes into the collecting of the planes and cites scenes based on real incidents.
If you like World War II films, this sprawling tribute to the RAF is for you.
