I just want to point out that those car CO2 figures don't go to very high fuel efficiency rates. I have a prius c (high on the efficiency scale, I know) and I just calculated about 290 grams of CO2 per mile (about 50mpg). Still not amazing, but a good bit better than 390g CO2/mile. That's just for one passenger as well.
Good point. Of course, modern 787s and A380s are also far more fuel efficient then then '60s and 70s era aircraft. According to Wikipedia, the 787 is 20% more efficient then a 767
People don't use cars to travel thousands of miles - especially as this topic was about speed of travel. So this per-mile statistic doesn't make flying any better as a form of travel. It's like comparing safety of moon rockets vs bicycling per mile of traveled.
Secondly, the co2 injected directly into the upper atmosphere has ~3x the warming effect as co2 emissions
released by cars.
If we look at an hour of flying vs an hour of driving,
the air traveler contributes 20-30x as much to global warming.
Of course 1-2 passanger car travel is horrendously bad as well, especially if you do it daily...
A 65% full 737 produces 184 grams of CO2 per passenger mile. An 80% full 747 produces 162 gCO2/ per passenger mile. [1]
A car produces between 390 and 600 grams of CO2 per mile. [2]
So if your car is efficient, and you're carrying more then two people, you can barely beat the efficiency of 40+ year old aircraft.
[1] http://www.carbonindependent.org/sources_aviation.htm [2] http://www.carbonindependent.org/sources_car.htm