When going from San Francisco to Los Angeles, Which is more green Flying or Driving. A recent article in VIA magazine raised this question and found that for two people, driving resulted in few greenhouse gas emissions by about 6%.  Flying was cheaper, took less time, and had more than an order of magnitude less change of a fatal accident.  If you had 4 people in the car, driving would be a lot more green.

When you take in all the data points, on a short journey like this, flying or driving does not make a big difference in eco friendly green-ness.  Someday (2018?) the new high speed train will be available as a more green option.