Subsonic jet transport has been with us now for about a quarter of a century. There are young people starting their careers today who have never known a sky without jet noise and the V-wing silhouette of a passenger carrying aircraft. Indeed, it must seem to them as permanent a feature of our world as the steam train between the world wars was to people such as myself; the big difference is, as I hope to show, that air transport has not yet reached a development plateau.

Aviation has always been a dynamic industry, with a rapidly expanding technology and opportunity which has now taken it beyond the atmosphere, into space and onto the planets. The spectacular steps have not been taken in the first place for the benefit of commercial transport operations—although there have often been consequential advantages. Advances were pursued because they were thought necessary for the maintenance of effective armed forces and the provision of efficient weapons.