Per the CDC its likely not the reciculated air, which uses HEPA filtration and catches 99.9% of particles.
It’s the inconsiderate schmuck sitting nearby who’s hacking all over you.
They ought to be quizing passengers to weed out anyone with upper respiratory symptoms.
I would only rarely have any reason to get on a plane, so not an issue for me.
And I’d take a pass even on free fares, anyway - at least until April. Feel for folks who have to fly for whatever reason, though.