Air travel does not pose a health problem to the vast majority of passengers. This page will help you understand that when travelling by air:
The CAA has a general duty to safe guard the health of all persons on board aircraft. This duty includes both passengers and air crew. The Aviation Health Unit provides information on the health aspects of air travel to health care professions, air crew and passengers.
Passenger health issues and concerns can range from whether they need to be assessed to fly through to whether they can carry their medication on board. Detailed information on the range of frequently asked questions from passengers can be found at the CAA Aviation Health Unit website.
The CAA provide a comprehensive guide on a range of other issues. You should refer to their website for guidance and help.
You should read the advice and guidance on the CAA website in the first instance if you have a complaint about your flying experience.