Golden Nugget
While I think that your answer is informative and more suited to this forum, I think the original poster was looking at it the other way round, e.g. what damage does the aircraft cause to the environment.
Vague things like global warming vs autos, wars, destruction of trees for agricultural purposes etc.
The aircraft postulated causes are measurable and taxable, while the others are not. Hence the need to put some restrictions on the alarming growth in airtravel and the jobs and salaries that go with it.
sarcasim mode off