Since the advent of air transport half a century ago, safety has been a dominating influence in aeroplane design. It is by no means the only factor. The successful designer is one who uses his talents to arrive at the best balance between the competing demands of speed, reliability, comfort, and cost, while satisfying the demands of safety.

The fundamental reason why the aeroplane places high demands on the designer, perhaps to a greater degree than is the case with surface vehicles, is that the aeroplane proceeds on its way in defiance of gravity. It has to be light enough to fly, and it cannot stop for running repairs. Working within the limitations of available materials and fuels, it took mankind a long time to discover how to make an aeroplane light enough to fly at all. It is a near miracle that some 70 years later, today's aircraft carry large loads for long distances with remarkable safety.