"People use air travel a lot, and it's very expensive. Not just in terms of money, either. It's also expensive for the Earth, since a lot of people rely on planes when travelling between Arctic communities, and airplanes emit more greenhouse gases than other methods of transportation, like boats or motor vehicles. Heavy goods and cargo are delivered by boat during the summer when there isn't so much ice to act as an obstacle, and by trucks when the water is frozen and sturdy enough for people to build ice roads."