Interesting that Air travel is quite competitive with other forms of transport. Especially if (and it's not clear how the numbers are worked out) the carbon footprint is per vehicle which can subsequently be divided amongst 100 odd passengers.
Some here would have us believe that air travel is the WORST polluter of all forms of transit. It's kind of like those people who complain about diesel buses carrying passengers (city or regional routes) and belching emissions, but fail to see that a full bus replaces numerous single occupant cars.