I spent some years in aviation (commercial air transport) so I...

I spent some years in aviation (commercial air transport) so I feel qualified to make a comment. There is a little truth to some commentary here, but a lot of facts are missing.
Firstly, modern commercial aircraft are fitted with HEMA filters in the cabin's a/c and ventilation system. They are rated to capture even the smaller range of microorganisms, like viruses and bacteria that make it into the air flow., 99.9% filtration, and law requires they be regularly changed.
IF you do get sick, it will likely be through a commonly used surface, like a toilet door latch. Swabs and tests done on random aircraft have revealed one of the most infected surfaces is the meal tray table, and when I fly I make it a habit of rubbing it down with alcohol based wipes, then disposing of them in a plastic bag destined for the trash. The issue with these tables is they are most often touched and breathed upon, but not properly scrubbed down post-flight. Nothing wrong with a bit of preventative care.
Aircraft are cleaned after a flight but it is usually rubbish collection followed by a disinfectant spray.
You're likely to get just as sick in an office, cafe or classroom.