Leeham writer Bjorn Fehrm has said that the aircraft recirculation system is effective in controlling spread of virus. Here is part 1 of a multi-part series.
In part 9, Fehrm says the HEPA filters in the cabin return path are hospital-grade and remove 99.9% of the viruses.
Fehrm also comments on the need to stay hydrated because the recirculated air is very dry.
Today Leeham has a different take, but not about the recirculation system. itself.
Why I Won't be Flying Soon
Please consider Pontifications: Why I Won't be Flying Soon by Scott Hamilton.
Some airlines block center seats. Others abandoned the practice recently or didn’t do so from the start. (When flights were operating 10% full, blocking seats didn’t matter.)
Blocking center seats really is cosmetic. Social distancing guidelines call for six feet between you and the next person. Blocking a center seat provides about 18 inches wide and 29-30 inches fore-and-aft.
The problem is not the airplane. It’s the people who fly. Passengers flying without masks put everyone at risk in those 2-4 minutes, as well as during enplaning and deplaning.
And most airlines aren’t enforcing a mask policy. The federal government won’t issue a rule requiring masks. Containing the virus requires passenger cooperation. It’s not there yet.
User's Guide To Masks
NPR has User's Guide To Masks that some may be interested in.