There is a way to make sure both you and your bike are on the plane before it can take off (IIRC it's called flagging?). I was coming back from the '99 MTBR Spring Fling in Phoenix, had checked in, was sitting in the bar with friends having a few (pre 9/11), and lost track of the time. They had to send someone to find me. There were 135 people in a 136 seat plane that were not amused when I finally stumbled on board.