The revolution of air travel between 1945 and 1969 contributed greatly to tourism in the United States. In that quarter century, commercial aviation evolved from 28-passenger airliners flying at less than 200 mph (320 km/h) to 150-passenger jetliners cruising continents at 600 mph (970 km/h).During this time, air travel in the U.S. evolved from a novelty into a routine for business travelers and vacationers alike. Rapid developments in aviation technology, economic prosperity in the United States and the demand for air travel all contributed to the early beginnings of commercial aviation in the US.