"It starts with Thanksgiving dinner in 1937. Walter Frederick Morrison and his girlfriend (later wife) Lucille started a game of catch with a metal lid from a popcorn container. The pair had a good time with it, but discovered that the popcorn tin lids were easy to dent, and subsequently, no longer great for flying. They started using cake pans to play; they were easier to find, and cheap to buy."
https://www.saturdayeveningpost.com/2021/09/the-surprisingly-complicated-history-of-the-frisbee/