During ww2, American bombers were bombing Bremen, and a bomber was severely damaged by German fighters. Fighter pilot Franz Stigler, recently rearmed and refueled, caught up with the retreating bomber in his BF109, and could see through the damages the injured crew. Instead of finishing it off, he stayed close to the bomber so that german Anti-Air would not target them. He tried to mouth and gesture for them to fly to Sweden to get aid, but pilot Charlie brown and crew didn't understand. Franz then maintained the escort until they were over open water.
Franz did this because he considered finishing a damaged plane with the injured crew the same as shooting parachuting pilots, which was (and is) a war crime.
Charlie Brown 50 years later managed to find Franz and they became friends until Franz's death.