Designing aircraft for the next century

The process of designing has two parts: the function to be performed by the aircraft and the optimising process whereby an initial design is improved to satisfy a wide range of requirements, both technical and economic. The first part draws on my 60 years experience(1) of aerospace design from which I have learnt how to deal with the initial ignorance at the start of a new project. The next section describes some new technology and configurations likely to mature for civil and military aircraft. Then I suggest some hitherto untried applications of aeronautics such as re-vegetation of arid regions, third world transport and maritime air vehicles. Finally, and considering the later part of next century. I venture into some revolutionary propulsion concepts that could dramatically change aeronautics.