Yes. Flying is very different in this respect from cars/trains: > "Half of the work done by a plane goes into staying up; the other half goes into keeping goin

Yes. Flying is very different in this respect from cars/trains: > "Half of the work done by a plane goes into staying up; the other half goes into keeping going." therefore: > "The plane was going anyway, so my flying was energy-neutral." > This is false for two reasons. First, your extra weight on the plane requires extra energy to be consumed in keeping you up. Second, airlines respond to demand by flying more planes. Quotes taken from "Sustainable Energy - without the hot air." by David McKay - University of Cambridge. The book is available free here: http://www.withouthotair.com/Contents.html http://www.withouthotair.com/Contents.html the chapter about plane physics is here: http://www.inference.phy.cam.ac.uk/withouthotair/cC/page_269.shtml http://www.inference.phy.cam.ac.uk/withouthotair/cC/page_269...