[Normal_gaussian]

I haven't seen anywhere suggesting that the transmission vectors between passengers are a major cause of the growth into a pandemic - even if that was the case, I doubt a once in 50 year disease is cause for them to change to a less profitable seating setup the other 49.

[londons_explore]

There are lots of cases of diseases spreading from one plane passenger to another.

That's part of the reason the airline requires you to sit in allocated seats - so they can notify the people sitting in neighbouring seats if you have a notifiable disease.

My personal hypothesis is the low pressure ultra-low humidity air in planes dries out mucus membranes in the nose and throat making it more likely for airborne things to get in.