Hello David, and thank you so much for this post - the film doesn't appear in cinemas here until January 11th, but I'll certainly be going - the trailers look outstanding and reviews have been very positive especially about Oldman's Churchill. In some ways it is symbolic and apposite that a working class kid from South London, whose family would very likely have been through the blitz, got to play Churchill. And I agree that the film certainly has deep connection with this group build as the RAF has been held in such reverence as a direct result of its sacrifice and indomitability in staving off invasion, an effort which ultimately ensured that any decision to negotiate in 1940 was rendered unnecessary.
Over the last couple of years I have read the first two volumes of Churchill's books on WWII which cover this period (I hope to get through the remaining volumes in the 'nearish' future!). I can highly recommend them too - much like this film, I suspect, they bring a reality to the meetings and decision-making of the time, omitted by the more popular accounts of front-line action. In his own writing he was plain-spoken and never much mythologised his own role, despite some (understandable) pride.
Given that Churchill had spectres of his past decisions in war to wrestle with too (and it is well-documented that many still disagree with some of his decisions later in the war) it must also be a measure of his mettle that his leadership of the British people saw them through that tipping point. Given that those previous decisions resulted in such losses, the resolve to commit the (young) fliers of the RAF (and beyond) to the fight, must have been incredibly hard to muster.