If someone travels around the globe in an airplane from east to west ( the same direction as Magellan ) , they should subtract one hour for every 15 Â of longitude crossed , losing 24 hours for one circuit of the globe ; but 24 hours are added when crossing the International Date Line ( from east to west ) . If one flies round the world from east to west ( the same direction as Magellan ) , one hour is lost for every 15 Â of longitude crossed , losing 24 hours for one circuit of the globe ; one compensates by adding 24 hours when crossing the International Date Line ( also from east to west ) .