Was on a KLM flight from ORD to AMS back in approx 1995, and the guy immediately behind me died. He actually didn't die until after we made an unscheduled pit-stop in Gander, and they took him off in a stretcher. He was obviously having a lot of trouble breathing, and no one could understand him (he was from Lithuania), so they made the unscheduled stop. When we finally got to Amsterdam, I inquired about him; he had died.