International air transport grew at double-digit rates from its earliest post-1945 days until the first oil crisis in 1973. Much of the impetus for this growth came from technical innovation. The introduction of turbo-propeller aircraft in the early 1950s, transatlantic jets in 1958, wide-bodied aircraft and high by-pass engines in 1970 and later, advanced avionics were the main innovations. They brought higher speeds, greater size, better unit cost control and, as a result, lower real fares and rates. Combined with increased real incomes and more leisure time, the effect was an explosion in demand for air travel