Travelers 1 into two categories: those who make lists and those who do not. Some people prefer to plan the course of their trip to the 2 detail. For others the joy of a trip is its spontaneity. Neither 3 works perfectly in South America. It is an area 4 requires considerable preparation: internal flights often run only once or twice a week, and an advance 5 can mean the difference between continuing to a new city and waiting several days for another flight.