By the year 2025, more than nine billion people will move through airports around the globe annually — more than double the number of passengers in 2005, an industry body said Tuesday.

In anticipation of the sharp increase, airlines, air traffic bodies and governments must work together and continually expand the 1,659 airports around the globe, says Robert J. Aaronson, director general of the Airports Council International, an association of airport operators.

"If the development of essential infrastructure does not keep pace, customer comfort will suffer — a vital message that must be understood by our industry partners, regulators and governments," Aaronson said in a statement.

The ACI estimates that passenger volumes will increase by an annual average of four per cent over a 20-year span. Asia is expected to lead the world with a growth rate of nine per cent until 2009. By 2025, Asia is expected to offer a formidable challenge to North America as the largest air travel market.

"Both the scale and speed of growth indicated by this latest forecast represent a daunting challenge for airports," Aaronson said.

"Given the current pace of construction and constraints on airport expansion, many airports may be facing a serious capacity shortfall if unable to urgently address infrastructure needs."

Canada's largest airport, Toronto's Pearson International Airport, ranked 29th in 2005 air travel with 29,914,750 arrivals and departures, according to the ACI. By comparison, Atlanta topped the list at 85,907,423. Chicago, London, Tokyo and Los Angeles rounded out the top five.

Aaronson noted that current travel patterns indicate there will be a shift toward using larger aircraft. The ACI says that aircraft manufacturers are currently developing more fuel-efficient and environmentally friendly aircraft.