So I have been flying a few years now. My problem is that I always feel like I'm fighting off some kind of cold. I feel that I'm constantly catching viral infection such as colds and flu and other things I wouldent like to say. And I know 100% this is due to the unsanitary place they call the aircraft lol. Any recommendations to staying healthy while on board and minimising the chances of becoming unwell. I'm short haul crew so I'm flying 4-5 days a week.

Water - Drink a ton of water. Being in the air a lot tends to dehydrate you much quicker than normal so drinking more than the recommended 2 liters a day is important.

Supplements - I use Tumeric, Probiotics, Fish oil, Daily Vitamin, and B12. Different supplements work better for some more than others so you just have to mess around with what helps your body more. These things are not instant so consistency is very important. Bring a small ziplock with enough pills for your long trips.

Wash Hands/Hand Sanitizer - Travel size kept near you at all times. If you close all the overhead bins then sanitize or wash your hands after. I know peoples hands get dry up there so be mindful of that. Keep your hands away from touching your face.

Exercise regularly - This one speaks for itself. Even if your tired just get 15 minutes in a day.

If the hotels ever have a sauna or steam room then use those as well. This helps dramatically with clearing up your respiratory system.