I would wear an N95 or P100 mask in the airport and on the plane (I also am experienced with fluid/gas flow through porous media [masks, filters...]). If you are sitting next to a contagious person for hours, proximity and viral load trumps ventilation in enclosed spaces.
I was on a superspreader biking event in March, and we were asymptomatic when we flew back, but covid hit us a day or two later. At least by wearing a mask I hope I didn't infect others. You can be contagious before the symptoms hit, and some folk are asymtomatic to covid. Almost no one on flights wears a mask. At least after 8 months my long covid is gone, but am a bit skittish about being exposed to covid again.