I did not know that about the HEPA filters and replacing the air every 4 minutes. I just assumed it was recycled and I just know that I often end up some kind of sick after flying. Of course, that could just be caused by the general stress of travel.
But, to be really safe and make the public feel safe, they are going to need to be able to actually test people for the virus because, as you know, many carriers are asymptomatic. Also, do we know if HEPA filters catch things as small as the corona virus? IIRC, its around .5 to 1 micron in size.
My hope is that this may lead to the airlines treating customers better because frankly flying has become a really miserable and something I hate to do. I only do it when I have no other choice and that's usually only for business purposes. But, I'm not holding my breath that the airlines will treat people better. I'm not sure if they are all doing it, but I saw some photos take by passengers this weekend on packed 747s with every seat occupied. Everyone appeared to be wearing masks, but I don't think that is going to be enough in a confined space.