Which if taken to it's logical(?) conclussion means we really should resort to moving from A to B upon donkeys, does it not ?
Ah but, herds of Donkeys will generate methane and other green house gases ( as do lakes, dams, and resevoirs - but we don't hear much about that issue do we ? ).
As for the 74 cars, well they will have to be manufactured ( which uses an afwul lot of energy ) and they typically don't last as long as aeroplanes ( certainly not if one was to operate them as hard as a jet has to work - e.g. 14 hours per day, every day, year in year out ) so they'll have to be replaced ( more manufacturing ), to say nothing of the fact that they will cause more congestiion on the roads ( so better build some more roads).
So which is the more environmentally friendly - the aeroplane, the car, or the donkey ?
I jest, of course - but if only it were as easy as saying cars good, aeroplanes bad, or cars bad, donkeys good - but some would like us to believe that this is so.