I would just like to add, that the general person uses a car a lot more often than a plane - and it all adds up.
A lot of cars are used by a single person. Almost never (generalised) to it's full potential.
I'm uncertain about this, but I think most planes are very well utilised (closer to the full potential rather than to the opposite) - since it's so uneconomical to go empty or close to empty utilisation.
I'm not however disputing that a plane emits a lot more emissions than road bound vehicles.
"the general person uses a car a lot more often than a plane"
Average CO2 per person in the US is around 17 tonnes per year[1].
A single flight from LA to NYC (round trip) is equivalent to about 2 tonnes after taking into account some high-altitude effect[2].
Driving 12,000 miles per year at 25mpg releases about 4 tonnes[3].
So, if you cut your driving in half and then take one long domestic flight, you are just breaking even. If you take multiple long flights per year, you really have no hope of staying below the average carbon footprint for an american. Unless maybe you live in a tree or something.
I'm not saying this to be critical. I fly, and I am not ashamed of that. But we should be honest with ourselves, and not think that riding a bus once in a while and buying locally-sourced vegetables makes up for taking three international trips a year.
A lot of cars are used by a single person. Almost never (generalised) to it's full potential.
I'm uncertain about this, but I think most planes are very well utilised (closer to the full potential rather than to the opposite) - since it's so uneconomical to go empty or close to empty utilisation.
I'm not however disputing that a plane emits a lot more emissions than road bound vehicles.