Why don't airlines place some physical separator between passengers in the planes to prevent the spread of COVID-19?
A bit like the following, but adapted for cabins and viruses:
Aviation Stack Exchange is a question and answer site for aircraft pilots, mechanics, and enthusiasts. It only takes a minute to sign up.Sign up to join this community
Masks are very effective, cheap, and people are quite willing to use them (excluding some mentally challenged cases). The ventilation in planes is also rather safe when considering the spreading of viruses (see this ASE Q&A), especially when combined with the use of masks. Planes usually have very good filtering of recycled air, and much of the air is not even recycled.