Source: Airlines for America. IATA.
Air transportation has experienced rapid growth since the 1970s, with air freight growth similar to that of passenger traffic. The growth of air traffic has also been characterized by several setbacks linked with recessions (1973-1975; 1980-1984; 1990-1991; Asian Crisis of 1997; the Financial Crisis of 2008-2009), geopolitical instability (Gulf War of 1991; September 11, 2001) and even the COVID-19 pandemic (2020-21). The latter represents the most significant singular event affecting the airline industry, notably the passenger segment, which experienced a 65% drop in 2020. Despite these setbacks, the rapid rebound in traffic in some markets points to buoyant air traffic demand. Growth resumed its pre-pandemic trajectory and will level off as developing economies such as China, India, and Brazil mature into mature markets.
The main factors behind the growth in passenger and freight traffic, as measured in passenger-km or ton-km, are linked to greater volumes carried and the average distance over which passengers and freight are carried. The changing structure of air transport networks is also at play, as the development of hubs involves fewer direct connections and, therefore, longer average distances between airport pairs. The development of passenger services tends to increase freight supply, since each additional plane typically offers additional cargo capacity that can be made available on the market. This additional capacity can catalyze new cargo demand.