@cholash Yes, masking helps with most respiratory illnesses, even MAC, I believe. But for me, every respiratory illness raises the real possibility of an exacerbation, which can cause weeks of poor health, and especially, set off my coughing again.
I cannot accept that 200+ people in a crowded waiting area and jetway, then in a long skinny tube, breathing, coughing, and sneezing, are not a risk - I keep my mask on except when eating or drinking. Besides, we don't always know how well the ventilation system is working. I flew thousands of miles last fall, including 4 flights in 5 days, and managed to not catch anything. Back in my working days, when I flew almost weekly, I caught a cold or other "bug" on about every third or fourth flight - and that was years before my Bronchiectasis was diagnosed.