Lookleft, I haven’t kept up with what the airflow models are inside the cabin these days, all I seem to remember is that bleed air cost money, smokers were at the rear and the state of the cabin outflow valves at overhaul was just disgusting. Is it possible that the covid infected cruise passengers were sitting in a spot where there was not much recirculation? Maybe if they were in 1A and B they might have infected a plane load?