I'm a history buff and just finished reading "A Higher Call," by Adam Makos. It's a great, well-paced book about a true-life World War II mid-air encounter between the critically wounded crew of a badly damaged American B-17 bomber and a German 109 pilot, Franz Stigler.
Stigler, upon encountering the B-17 flying alone in enemy airspace, was a German Air Force ace who easily could have blown the Americans out of the sky. After seeing the badly damaged, open-to-the-air plane, its already-dead tail gunner, and the rest of the crew hanging on for dear life and trying to care for each other while their pilot, Charles L. Brown, worked to keep their defenseless, lame-duck plane aloft in enemy territory, however, Stigler made his own unauthorized decision not to shoot the Americans down.
Instead, he flew in formation on the B-17's wing and escorted it safely past a coastline full of German flak gunners in a tense encounter that was considered classified information in the U.S. for years afterward. It was an act that also could have meant death by firing squad for Stigler if he was ever connected to the incident.
The book tells the stories of both pilots over the years, puts the reader right in the middle of their transcendent Dec. 20, 1943 encounter, and follows them right through to their eventual in-person meeting with each other in the U.S. nearly 47 years later, despite the fact that they had never spoken, didn't know each other's names, and had no current information on each other's whereabouts.
I highly recommend this book if you're interested in this kind of thing. It's compelling material, and it was easy to read. I was hard-pressed to put the book (or rather, my Kindle) down once I got started, and I polished it off in two days.