Also as Barnes Wallis in The Dambusters, I would add in Richard Todd as Guy Gibson, that final scene after the Raid where he walks away from Redgrave because he has to write a few letters is heartbreaking.
David Niven in a Matter of Life & Death. If you can leave the opening scene when he is about to jump from his Lancaster without a parachute having spoken to Kim Hunter playing a Ground Control Operative dry eyed you are a strange person.