Yes, an amazing generation. One of my uncles was on a B-24 that was shot-down, and had to endure ill health as a POW. (I do not know whether he was a POW by D-Day.)
My future father-in-law was part of the organized AK resistance against the German occupation of Poland. A professional-level violinist, and a grandson of Antonin Dvorak, he earned favor among German officers by playing music, and raised silkworms to produce silk for German parachute lines, but behind the scenes, he helped hide at least one Jew, and forged documents used by resistance folks. Not being a communist, he had to go further underground after being “liberated,” and his hiding in Czechoslovakia, and subsequent escape, through the forests, to the American sector of Germany, is an example of truth being more amazing than fiction. (Being part Czech, he could hide, for a while, with an uncle.)
We will probably never know whether he was a spy, for Poland, before WW II started. My father-in-law spoke of traveling, with a companion, along the border in a collapsible decked canoe, that we may call a kayak today, just before the war. He said that “we were lucky we were not shot for spying.” When asked, well, what were you doing, he would grin, say, “spying,” then laugh, and change the subject.