Two things that are out of scope for this article: Emission altitude may change how certain emissions affect the environment and specifically the climate: "Emis

Two things that are out of scope for this article: Emission altitude may change how certain emissions affect the environment and specifically the climate: "Emissions weighting factor (EWFs) i.e., the factor by which aviation CO2 emissions should be multiplied to get the CO2-equivalent emissions for annual fleet average conditions is in the range 1.3–2.9."[0] The other thing is that apart from the emissions per mile, you tend to travel more miles when you use a plane -- a magnitude more. Regardless of whether you take a car, a train or a plane, motorized mobility is only sustainable up to a point, and planes make it very easy to go (fly) beyond that point. [0] https://en.wikipedia.org/wiki/Energy_efficiency_in_transportation https://en.wikipedia.org/wiki/Energy_efficiency_in_transport...