may I also draw your attention to ’49th Parallel’ on Tuesday 8th, Channel 4 at 13.10 hrs. This is essentially a story about a U-boat crew escaping across Canada after they are sunk off the coast. If I remember correctly (and it’s ages since I’ve seen it) they are attacked by an aircraft which starts off as a Maryland on the run in, changes into a Hudson as it bombs, and climbs away as a DC-3! It was made in 1941, and I daresay they thought nobody would notice.