Unrestricted travel

250 million travellers use international scheduled services a year -- equivalent to one in every five of the world's population. In 1994 it was estimated that the income elasticity of air traffic in Western European countries is 2.4, which means that a 1 percent increase in income leads to an increase of 2.4 percent in air traffic. As a consequence, air traffic is currently growing a an annual rate of 5 percent and is expected to double every 14 years.

During the last 30 years, vehicle ownership and use in OECD countries has risen dramatically -- from 2,584 billion kilometres travelled in 1970 in passenger cars to a doubling by 1991 to 5,068 billion kilometres.

In 2000, 2 million people were crossing international borders every day.