I came across this one a few days ago, as Sir Douglas Bader died on September 5th 1982.

Sir Douglas was giving a talk about his experiences in the War to an assembly of girls in a very posh private school:-
"There were two fuckers to my left, two fuckers to my right and even more fuckers behind me."
The headmistress went very pale, stood up and announced to the girls, "A Fokker was a German aircraft, girls."
Bader replied, "True Ma'am, but these fuckers were Messerschmitts!"

(It's apocryphal of course)