ABSTRACT
Compared to the automobile, light aircraft have a relatively small environmental impact. An automobile requires a continuous road for the entire length of a journey, while a small airplane only needs a short runway at the beginning and at the end. Roads are bad news for the environment, breaking up habitat into smaller pieces and thereby reducing the diversity of species per unit of habitat. While general aviation aircraft are less damaging than cars, they emit two sources of pollution that dwarf those of the automobile. Aviation gasoline, or avgas, contains tetra-ethyl lead, a toxin that causes brain damage in children. Lead has been removed from automotive fuel, except for some racing fuel. The second pollutant is excessive aircraft noise, primarily from a poorly muffled engine exhaust and a propeller with sonic tips. Neither of these pollutants is essential for flight. The technological solutions are straightforward, but expensive. In a society in which the polluter does not have to pay for the damage, it is cheaper for them to pollute. The legal system also discourages improvements to aircraft because of liability laws.
