Admit it. At one time or another, you've been guilty of taking an unnecessary trip that wasted energy, generated pollution, and helped contribute to global warming. In fact, it's probably safe to say that until recently very few among us considered the fate of the planet when making our travel plans%u2014price and convenience, sure, but not fuel burn. However, when it comes to recklessly disregarding our carbon footprints, I doubt you're as guilty as I am. After all, I once sent an empty Boeing 727 on a 184-mile journey.