UPDATE — from a reader:
My father had the sine qua non of Snakes on a Plane stories. He was a USAF pilot, and flew the bodies of our dead servicemen home in C-141 Starlifters during Vietnam (I can’t go the the Vietnam Memorial without wondering how many of those men he flew home). He’d take cargo over from McCord, and bodies back via Hickam. One flight they encountered a strong jet stream headwind and were behind schedule, landing after dark in a monsoon rain. The coffins were on pallets wrapped in plastic, and were loaded hurriedly by a forklift. Once refueled and back in the air, the navigator told my dad and the co-pilot that he wanted to stretch his legs and walk around the cargo compartment.
There is a pressure bulkhead with an air tight door between the cockpit and the cargo compartment, and my dad said the navigator opened it, stepped through, and closed it behind him. Within seconds the door swung back open and the navigator dived into the cockpit. My dad told the conversation like this:
Dad: “What seems to be the problem, captain?”
Navigator: “Snakes, Colonel Pepper! Millions of them!”
Dad to co-pilot: “Take over for a minute, would you Major?”
So, dad looks through the door to the cargo compartment only to find that the loading deck is completely covered with writhing snakes of various kinds. Not millions, but certainly hundreds. They had evidently took shelter in the pallets, and when the cargo compartment got cold, decamped to look for someplace warmer. The solution dad came up with was brilliant: The took the 141 up close to its service ceiling and depressurized the cargo compartment, killing all of the snakes. Then, they went down to the deck, opened up the rear cargo door, and swept them out over the Pacific.