Pressurized airplanes have air changes per hour in the 12-16 range. That's above the ASHRAE recommended 6-12 air changes per hour for places that may contain viruses. (Obviously, ASHRAE isn't the CDC or healthcare organization directly, but they do know a few things about standards setting for HVAC.) Excellent filtration isn't as relevant when the average air molecule is in the aircraft for only 5-10 minutes.

The standard for AC/H for offices is 3-4.

The studied COVID outbreaks on planes show that this still isn't sufficient. I'm also pretty sure I got sick from the kid sitting directly behind me on the plane when I got influenza.

You can site all the statistics and propaganda in the world about plane ventilation. It clearly isn't enough to prevent viral spread (I don't care about air changes per hour or cfm or anything else, the only endpoint worth discussing is viral spread--I give precisely zero fucks about how fast the air is moving around). I'm using n95s on planes from here on out.

The real hazard is when you're on the ground. I've seen cabin C02 levels above 3000ppm when the cabin air handling hasn't been turned on!

I'll take my mask off to eat/drink in the air, which I didn't do the one time I had to fly mid-pandemic.