The only time that I was supposed to travel and the captain did not show up was on USAirways and he did try to show up. However, when he fainted while going through security was a clear sign that he had a serious health problem that required emergency surgery. Passengers flying Business Class were immediately transferred to LH flights. My wife and I had to wait for a flight the next day to return to the US but we got upgraded in the process. And, the next day, we heard that the surgery went well. We are still glad that it happened at the airport and not mid-air.