Many British people like to travel to Spain, Italy and other warm countries for their holiday. They want to live in the sun for a few weeks and many of them like to take their cars on holiday with them. Then they can travel round the warm countries and see many places in a short time. But them is a problem. It is only twenty-two miles from Dover in England to Calais in France, but between the two towns there is the English Channel. It is necessary to take the cars across the sea, and this is not easy. Some passengers put their cars on a plane and fly across with them, but that is expensive. Others drive their cars onto large ferries. This is cheap, but the boats are slow and sometimes the sea is rough. These days, more and more people choose to travel by hovercraft. This passage is chiefly about ______.