The point about airplanes not running the ventilation on full throttle till takeoff has always driven me crazy. It's bad enough by itself, but it's also the time that lots of people are walking around. One sick person slowly making their way to the back of the plane while constantly waiting for people in front of them to put their luggage up will spread viruses throughout the entire plane, not just the folks within a few rows of them. This is the time when I most want the airplane to feel like wind tunnel. The economy looses billions every year to flu, cold and now COVID. If we can reduce that via ventilation (and maybe far-range UVC-C lights) in public spaces, we absolutely should. It's gonna pay for itself in no time. But it's a collective action problem where the costs are localized but the benefits help everyone.