I had visitors from Europe the last couple of weeks, coming on 5 different flights. The visitors on three of these five flights developed covid-19 2 or 3 days after arrival.
They were all between 50 and 65.
Three guys on the same flight of Thai Airways got all infected. They had their fourth vaccine just one month before the flight, the symptoms were only a common cold. Lasted a couple of days.
Another guy on a different flight was sick (more or less bed ridden) here for one week.
Still another guy on another non-stop flight was sick for almost 3 weeks, he also infected his Thai girlfriend who also was sick for about 3 weeks.
I discussed this with a friend who is a flight surgeon: "this was to be expected".
BTW TG encourages passengers to wear a mask. Emirates, I was told, encourages passengers not to wear a mask because the air in their planes is clean.