The Asia-Pacific region is expected to be the source of more than half the new airline passengers over the next 20 years.

China will displace the US as the world’s largest aviation market by around 2029.

India will overtake the UK for third place in 2026, while Indonesia enters the top ten at the expense of Italy.

Growth will also increasingly be driven within developing markets.

Over the past decade the developing world’s share of total passenger traffic has risen from 24% to nearly 40%, and this trend is set to continue.

The projections come in Iata’s latest 20-year passenger forecast which estimates a near doubling of global passengers from 3.8 billion this year to 7.2 billion in 2035.

The forecast puts forward three scenarios. The central scenario foresees a doubling of passengers with a 3.7% annual compound annual growth rate.

If trade liberalisation gathers pace, demand could triple the 2015 level.

Conversely, if the current trend towards trade protectionism gathers strength, growth could cool to 2.5% annual growth which would see passenger numbers only reach 5.8 billion by 2035.

The five fastest-growing markets in terms of additional passengers per year over the forecast period will be:

• China (817 million new passengers for a total of 1.3 billion)
• US (484 million new passengers for a total of 1.1 billion)
• India (322 million new passengers for a total of 442 million)
• Indonesia (135 million new passengers for a total of 242 million)
• Vietnam (112 million new passengers for a total of 150 million).

The top ten fastest-growing markets in percentage terms will be in Africa: Sierra Leone, Guinea, Central African Republic, Benin, Mali, Rwanda, Togo, Uganda, Zambia and Madagascar.

Each of these markets is expected to grow by more than 8% each year on average over the next 20 years, doubling in size each decade.

Routes to, from and within Asia-Pacific will see an extra 1.8 billion annual passengers by 2035, for an overall market size of 3.1 billion. Its annual average growth rate of 4.7% will be the second-highest, behind the Middle East.

The North American region will grow by 2.8% a year and in 2035 will carry a total of 1.3 billion passengers, an additional 536 million passengers per year.

Europe will have the slowest growth rate, 2.5%, but will still add an additional 570 million passengers a year. The total market will be 1.5 billion passengers.

Latin American markets will grow by 3.8%, serving a total of 658 million passengers, an additional 345 million passengers annually compared to today.

The Middle East will grow strongly by 5% and will see an extra 258 million passengers a year on routes to, from and within the region by 2035. The UAE, Qatar and Saudi Arabia will all enjoy strong growth of 6.3%, 4.7%, and 4.1% respectively. The total market size will be 414 million passengers.

Africa will grow by 5.1%. By 2035 it will see an extra 192 million passengers a year for a total market of 303 million passengers.

Iata director general and chief executive Alexandre de Juniac said: “People want to fly. Demand for air travel over the next two decades is set to double.

“Enabling people and nations to trade, explore, and share the benefits of innovation and economic prosperity makes our world a better place.

“Economic growth is the only durable solution for the world’s current economic woes. Yet we see governments raising barriers to trade rather than making it easier.

“If this continues in the long-term, it will mean slower growth and the world will be poorer for it.

“For aviation, the protectionist scenario could see growth slowing to as low as 2.5% annually. Not only will that mean fewer new aviation jobs, it will mean that instead of 7.2 billion travelers in 2035, we will have 5.8 billion. The economic impact of that will be broad and hard-felt.”