A flight is a fucking sardine tube. You're packed in tight with other people for hours breathing recycled air. There will be way more transmission on a flight than a restaurant or even most forms of public transit.

This lady knew she was required to wear a mask, because the airlines spam you with notifications about it and it has been that way for months. She held up a flight because she decided she deserved to be considered above the rules, which definitely makes her seem like a Karen. When we're talking about holding up a fucking flight, I wouldn't care if it turned out masks didn't do anything. They're a minor inconvenience, and if you really feel that strongly about it, then feel free to take it off after we're already in the air. That way if they decide to arrest you over your nonsense, it's only a minimal inconvenience to the rest of us.