Neither motor sport nor light aviation produce much if any measureable effect on the environment, but a great deal of people enjoy one or both. The societal cost for either is irrelevant. However, motor sport on tracks is more easily containable, therefore less threatening in its freedom, and a better opiate for the masses in terms of spectator appeal. Therefore it enjoys more government support in countries where personal freedom is seen as threatening and/or high population density means individual activity is more disruptive than spectator sport.