I'm more concerned about the airport than the actual plane. The plane should have pretty good filtration systems. Make sure you have the blower on and pointed at you, and you should be OK, unless someone with Covid coughs right in your freakin' face. I'm less confident about the ventilation in the airport, especially given the inconsistent mask wearing you witnessed.I am much more concerned about the airport/plane.
Given the empty state of the parks, I almost booked a last minute father/son trip. What held me back was the time in the airport--not the actual flights. Also, the park tickets would have been more expensive than the flights and a one-bedroom at WBC combined!