Aviation medicine is a recent and rising field of medicine, as air travel becomes an increasingly important and accessible means of transportation. More people are travelling and doctors are now expected to properly advise and assess the medical conditions of their patients and give advice about their eligibility to fly.
Case Notes, a BBC Radio 4 health programme (www.bbc.co.uk/radio4/science/casenotes_20020820.shtml) gives a good introduction to the subject. The programme on aviation medicine is readily downloadable, and in half an hour of conversations with experts in the field, you will get a good overview of relevant practical issues, such as assessing patients' fitness to fly, answering patients' queries on flight related health questions, and medical evacuation, among others. There is even a chance to listen to a doctor who operated on a patient inflight. The programme is intended for laypeople, so do not expect a highly technical discussion.
The British Airways' website