Since a mask isn't going stop a respiratory virus from spreading to people confined with you for several straight hours, you should probably just cancel your flight, if you actually want to protect them from your illness.
Discussion
Nah, when people go in public they take the risk of encountering unhealthy people. Being sick doesn't make someone a second class citizen & suggesting otherwise really messed up. You bear the cost of keeping yourself healthy, you do not get to offload those costs onto everyone around you. You can always wear a hazmat suit if you want.
Do you believe in courtesy at all? Like if someone cuts you off it's your fault because you decided to drive? Most of us have to live in a society. If I could live in the woods, I might.
I do believe in common courtesy, like not demanding that others bear the costs of all of my personal concerns.