If you're afraid of flying, it's usually a more understandable fear - bad weather may bring your plane down, your pilot might screw something up, something on the plane might break. But a much more unlikely fear might be that someone on board might decide that in order to milk out a little insurance money, they're going to blow up the plane you're flying in, either to take themselves out or to get rid of someone they'd much rather do without. On November 1, 1955, just such a bomb knocked United Airlines Flight 629 out of the air. But just who was the culprit? And who was the target?