Go back to the start of the thread. The inference that seven were contagious when they boarded and nine caught it during the journey was from the Welsh public health authorities.
Air may be effectively filtered entering the cabin but CFD modelling shows it moves around quite a lot before exiting. Google it.
I haven’t ignored the Quantas post: I’m just not sure I understand it or what it is telling me.
The public health authorities obviously think you can catch Covid travelling by air: otherwise they wouldn’t have quarantined 186 passengers and the crew. And even if you don’t believe Covid is transmissible in flight the idea that if you are on a flight where someone has it you will have to quarantine for 14 days means the consequence is pretty much the same.
I don’t think the fig leaf masks currently required make a material difference in the context of a flight, so mask compliance (and getting up to go to the toilet) is not the real issue.
I know this view is not popular: but the validity of the message is not changed by shooting at the messenger. The industry is in denial, in a world of pain but self harming. It needs to eliminate queueing (end to end), improve terminal layouts, minimise contact, improve staff PPE compliance, take sanitation seriously, issue higher specification masks and ensure they are worn. What I see right now (limited sample, but particularly in the UK) is lip service and bluster.