evidence: Flying was very expensive. Only business travelers and the wealthy could afford to fly. Most people still rode trains or buses for intercity travel because flying was so expensive. A coast-to-coast round trip cost around $260, about half of the price of a new automobile. But despite the expense and discomforts, each year commercial aviation attracted thousands of new passengers willing to sample the advantages and adventure of flight. America's airline industry expanded rapidly, from carrying only 6,000 passengers in 1929 to more than 450,000 by 1934, to 1.2 million by 1938. Still, only a tiny fraction of the traveling public flew. [...] In 1955, for the first time, more people in the United States traveled by air than by train. By 1957 airliners had replaced ocean liners as the preferred means of crossing the Atlantic. [...] Hundreds of millions of passengers now fly each year in the United States. But that popularity has also brought crowded airplanes and congested airports and has dulled the luster air travel once had.