Are there any significant differences to the ecological impact of flying based on which airline you choose? The Guardian seems to suggest that maximizing economy seats per plane could help determine the best airline, though I don't know whether such information is available. Has anyone heard of other ways of determining this or if any airlines have any other promising initiatives?
Obviously, the ideal would be to eliminate air travel, but I'm sure I'm not the only one for whom this would have serious professional ramifications.