I have to fly from one end of Canada to another next week (i.e., from Vancouver to Halifax). I have a broken wrist. Should I be worried? Normally, I would think nothing of flying with a broken wing. However, in 2008, I lost a dear colleague who flew back to Canada from New Zealand after breaking his leg. His death was completely unexpected. I believe the cause of death was attributed to Deep Venous Thrombosis (a Blood Clot) in the leg; clots in the legs are not serious in themselves, unless they break off and travel to the lungs (called pulmonary embolism) causing chest pain and shortness of breath, and can be life threatening.
So, I tracked down a bit of information on the Aerospace Medical Association's website.
From their extensive document called, "MEDICAL GUIDELINES FOR AIRLINE PASSENGERS" published in 2002:
Fractures: Most passengers with treated fractures can travel safely by air. The only potential problem is swelling of the tissues under the cast that can occur due to a decrease in barometric pressure at altitude. This could interfere with healing and cause pain. In general, the risk of swelling is greatest the first 72 hours after the cast is set. It is, therefore, advisable to wait 3 days before traveling. However, if this is not possible, your physician can fix the cast in such a way that it can be loosened (by splitting it along the sides and wrapping with an elastic bandage—called bivalving), if necessary. A bivalved cast will probably have to be replaced at the destination.
Okay, then -- given that my cast will have been on for 5 days, I should be A-OK. I hope.