Remember the poo bus? Now meet its high flying cousin from across the pond. It doesn't have the same somewhat scandalous artwork of the UK Bio-Bus, but it will be running, or in this case, flying, on the same principles. Or the same waste materials, for that matter. United Airlines is planning to make a flight starting from Los Angeles International Airport to San Francisco running on fuel produced from farm waste and animal fat. Which is just a more sensational way of saying "biofuel".