The SF Chronicle just had an interesting article on how to travel green. The short, easy answer: there is no easy answer.
But to get the ball rolling on ideas, check out the Sierra Club's Green Getaway calculator: http://www.sierraclub.org/howgreen/getaway/.
Is driving a car the way to go. Well, depends on your choice of tranport. An economy car would be better than a plane if you have at least two people than a car. If your ride is an SUV or similar guzzler, you might be better off flying.
If you fly, the flight with stopover might be cheaper, but your carbon footprint goes way up. Makes sense - extra takeoffs and landings, not to mention the circuitous route you may have taken.
Check out the full SF Chronicle article at http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2008/05/08/DD6810HI7T.D...
