Planes today have a number of ways that they can check their current position including listening to a set of GPS (Global Positioning Satellites) in orbit around the earth. It is almost impossible for a pilot to get lost if he has the right equipment and uses it properly. In 1945, though, planes flying over water had to depend on knowing their starting point, how long and fast they had flown, and in what direction. If a pilot made a mistake with any of these figures, he was lost. Over the ocean there were no landmarks to set him right.