[telchar]

Don't discount the energy cost of air infrastructure in this comparison though. Airports have a huge amount of tarmac that must be built and maintained, there's the jet fuel production/transportation infrastructure, and of course building the planes themselves. Rail may have the larger overhead, but air has some too.

[jnxx]

Alone the amount of tarmac for jet runways is massive. It is also often concrete which has a massive CO2 impact.