How the vehicle is likely to be used is also a major consideration in
designing dual-purpose transportation. The average use of a privately owned,
general aviation aircraft is somewhere around fifty hours per year. It is
not uncommon for the same pilot to use his automobile fifty hours a month,
and in some cases he will use it fifty hours a week. Accordingly, a truly
practical flyable and drivable vehicle must be comfortable to fly, and also
it must be as comfortable to drive as a normal factory-produced automobile.
A normal production run for an automobile is at least two hundred thousand
units, and it can be as high as eight hundred thousand units. Development
costs and tooling make such high production runs essential for economic
The market for aircraft is considerably different. The latest year in
which figures are available for factory built aircraft is 1998. In that year
some 2,200 general aviation aircraft were produced. This figure does not
include homebuilts which might add several thousand or so, worldwide.
The introduction of a truly viable roadable aircraft would modify the demand for general aviation aircraft, but the degree of improvement is impossible to predict. It is certain that the demand for cars would still greatly outpace the demand for aircraft. Clearly, for an auto manufacturer to be interested in producing a dual-purpose vehicle, the inventor must come up with some way to accommodate such an imbalance in demand.