I'm 4 illnesses out of my last 5 flights. Flu twice, despite getting vaxed. The last one was a sinus infection so bad I'm afraid to fly again.

Previous doctor was just like "was your hands more", so he's fired. New doctor has a plan where I take supplements and some asthma steroids before travel and wear a mask through the flight.

My father is a sports pilot. As a child I flew very often with him. I puked almost all the time but I still loved hit. Every plane at his club is marked by my vomit.

Only one time I already felt sick when we arrived at the airfield. He still took me up in a sailplane. In order to stay up in a sailplane you have to constantly fly in circles above fields with warm air. Round and round and round. We were up for 4 hours. I didn't puke once. By the time we were back down again I wasn't sick anymore.

I don't, but there's always someone else in my family who's getting sick whenever we fly together. I've worn masks to the airport ever since the pandemic. Also tend to fall asleep shortly after takeoff, so I'm well-rested upon arrival.

Getting sick when traveling is absolutely more common, you're exposed to foods, diseases, weather, and people that you aren't used to. However if it's happening reliably and specifically after flying as opposed to other forms of travel that does sound like it could be a specific problem. It could be an inner-ear thing since airplane compression can fuck with that

It's not a perfect solution but sometimes when I fly I wear a mask to reduce the odds of getting sick, though it's pretty rare I get sick from travel myself, and I travel internationally annually

I usually buff up on immune system supplements a few days before travel, because the same used to happen to me.

At this point I seem to get sick once a month from having to go into the damned office