By 200 the number of global passengers is forecast to surpass the 5 billion mark and by 2025 there is expected to be in excess of 9 billion passengers globally, according to ACI.

Other Highlights:

• Overall, over the next 20 years world passenger volumes will rise by 4.0% annually. Annual growth rates for international flights (4.5%) will continue to outpace domestic (3.7%). 

• The domestic markets are however, expected to remain larger than the international market at 5.1 billion passengers vs 4.0 billion international passengers in 2025.

• Over the next 20 years aircraft movements are set to increase from 67.9 million in 2005 to 11 8.6 million movements by 2025 at an average annual growth rate of 2.8%.

• Over the next decade, North America will remain the largest aviation market but its overall market share is forecast to decline and by 2025 should account for only a quarter of all passengers globally.

Asia set to become the largest aviation market:

Asia in 2006 was the third largest region in the world but is forecast to become the largest aviation market by 2025. 

Asian air travel is set to increase 9% annually, led by India (10.4%) and China (8.1%), ACI said, reports Reuters.

Last year 1.5 billion people passed though North American airports, versus 897 million in Asia.

Asian freight volume in 2005 was 26 million tons, just 5 million behind North America, and Asia is expected to be the world's largest freight market by 2025, reports