[nmc]

You cannot make the cost-efficiency argument without acknowledging all the costs which aviation and automotive travel externalize: air and water pollution, damage to wildlife, global warming, lack of walking/cycling infrastructure, rising sea levels... a disproportionate part of which are born by poor or faraway people who have no choice in all this.

Edit: forgot about noise pollution and about flooding risks (due to impervious surfaces like runways and parking lots).

I also doubt airfields and planes require significantly less maintenance than trains and tracks, but I have not researched that.