Source: Air Transport Association and World Bank.
Over the period 1950-2016, air passenger and air freight traffic grew systematically faster than gross world product as the unique ability of air transportation to collapse space and time drew more traffic. Correlation analysis reveals significant associations; 0.65 (R square) for passengers-km and GWP (Gross World Product) and 0.75 for tons-km and GWP. Thus, each unit of economic growth is associated with a corresponding level of growth in passenger and cargo air transportation.
Air transportation endured a strong period of growth during the 1960s with passengers and freight growth systematically in the 10%-20% range. Airports were being increasingly congested and airline companies were looking for jet planes with higher capacities. The surge of passengers-km in 1970 (+31.1%) is mainly attributed to the introduction of the 747, a large capacity airplane that revolutionized air transportation by offering lower fares, high capacity and a longer range of operation (thus more passengers-km). The setback for air transportation came in 1973 with the Arab oil embargo and the subsequent recession (1974-1975). The 1981-1984 recession, the Gulf War (1991) and the Asian Financial Crisis (1997) were also economic setbacks that impacted air transportation. However, September 11, 2001, events, linked with a recession had considerable impacts on air transportation which experienced a global loss of 35 million passengers between 2000 and 2001. This was the second time in history that passenger air transport experienced a year of negative growth. The third occurrence of negative growth took place in 2009, the outcome of a major financial crisis and an issuing recession. The industry experienced a drop of 9 million passengers between 2008 and 2009.