I studied Hitchcock a little bit at University and knew the famous story about the Birds - that he'd tortured Tippi for a day using real birds. I had no idea that it was a five-day onslaught and that it was the tip of an iceberg that carried on through to another film.
“Nine g's is good, if the pilot can stand it. We couldn't stand it. Not in the airplanes of World War II.”