This could be a good plan if it is organised properly.....however there are lots of improvements that could be done around the airport to help the pollution/green issue; Many of the stands at LHR the fixed ground power does not work...check out the lovely new stands for the 380 (301-307) none of the power works on these stands and has been like that for weeks, the jettys are regularly failing, meaning buses for the passengers etc.....now a 747 APU running for a 3 hour t/round......towing to the runway would be good, but lets sort the basics out first....(cost theBAA money so they wont bother)