The figure is almost the double of this year’s 3.8 billion travellers and demonstrates a 3.7 percent compound annual growth rate (CAGR), which is in line with the central scenario outlined in IATA’s 20-Year Air Passenger Forecast.

Based on the second scheme, if trade liberalisation gathers pace, demand could even triple the 2015 level.

Conversely, if the current trend towards trade protectionism gains strength, development could lower to a 2.5 percent annual CAGR which would see passenger numbers stand at 5.8 billion by 2035.

“Runways, terminals, security and baggage systems, air traffic control, and a whole raft of other elements need to be expanded to be ready for the growing number of flyers.

It cannot be done by the industry alone,” stressed Alexandre de Juniac, CEO, IATA.