http://www.forbes.com/2009/08/25/american-medical-associatio...
http://gregmankiw.blogspot.com/2009/06/physicians-incomes-an...
This is also why residents have to suffer ridiculous hours. With the severe limitations on the number of people who can become doctors, the profession is characterized by an extreme workload.
It's seriously wrong. I, for one, would not want to be operated on by a surgeon who'd been working for 21 hours straight. Commercial pilots are limited to 40 flight hours per month, and what they do is a lot less complex than what doctors have to do.
The senior staff can pretty freely pick the longest and easiest flights with the most turnover time, and thus they can enjoy eating and sleeping, and probably some shopping or exercising as well. On the other hand, if you're a young co-pilot you are likely to get the shittiest flights and the worst possible schedule, and you will probably find yourself in situations where you've flown more than your fair share of hours straight and you still have to haul one last plane home. And wake up next morning at 6am to begin a new shift.
I must say that planes have autopilot but operations don't. That might not be of much consolence, however.
If you fly international with the majors, you're in good shape. Those guys make $200k easily, but those jobs are essentially inaccessible because the people who get them never retire. The rest make very little, and work a lot harder.