Sure, choosing to fly on a plane may not be the most fuel-efficient way to travel, but sometimes it's the only way to get to your destination. One way to help reduce your carbon footprint when you fly is to pack less. The more weight there is on a plane, the more fuel a plane burns in flight. If every passenger on a domestic flight packed 5 pounds less, it would save more than 60 million gallons of fuel every year. So, pack only what you really need and maybe leave all those extra shoes, books and other things behind.