So here's something I just found on YT in the comments for a video – about the DB Cooper thing.
"I have been skydiving since 1978 my last jump was a few years ago. Anyway I jumped in the early 80's with one of the flight attendants on the DB Cooper flight. She actually helped DB get his gear on. She didn't tell him she had made skydives herself as she was afraid he might make her go. She said the four chutes all had "issues" but was able to make one work by switching parts. He knew about parachutes!!"
love this guy:
https://youtu.be/ueXqSZZnjbA