Nowadays we enjoy a high level of safety in air transport. One generation ago, in the late 1940s, it was not so good. Two generations ago, when air transport began in the 1920s, safety was by today’s standards quite deplorable. For example, in UK passenger services, fatal accidents in the early 1920s occurred at a rate of one per half million aircraft-miles. In the first half of the present decade, the corresponding rate is around one per 500 million aircraft-miles. This represents an astonishing improvement of the order 1000-fold. To what extent this improvement came about to satisfy public demand, or as a result of pressure from the powers-that-be, or from a professional desire to do an increasingly good job, is hard to say. Probably all these motivating factors played a part.