My favourite film of all time. Even those who aren't into war films will get a lot out of it and find a lump in their throat at the end. Fans of RAF/war films will find plenty of period/procedural detail (and if you're like me, plenty of phrases with which to drive one's family mad!) Not a blood and guts film, and all the better and more profound for that.
As is often the case with older movies, there are no 'deleted scenes' or 'directors' commentary'. However, whilst some background might have been interesting, the film stands tall on its own and doesn't need any hype. Definitely one you'll watch over and over.
Just buy it!