GLOBAL demand for air freight increased 2.2 per cent in 2015, down from the five per cent growth in 2014, due to sluggish trade growth in Europe and Asia, according to International Air Transport Association (IATA) data.

"In 2011 air cargo revenue peaked at US$67 billion. In 2016 we are not expecting revenue to exceed $51 billion," said IATA director general Tony Tyler, former CEO of Hong Kong's Cathay Pacific Airways.

IATA said while the outlook for air freight and world trade remains fragile, there were some signs that declines in cargo demand were bottoming out.

In the first two months of last year, when labour strife at the US west coast ports, and a massive automobile recall in the US drove shippers to shift goods from ocean to air, overall air cargo traffic was up 7.5 per cent.

But since then it has become obvious that underlying growth in air freight traffic is weak.

Said IATA: "We have to adjust to the new normal of cargo growing in line with general rates of economic expansion."

Looking ahead, IATA said: "Indicators in the Eurozone are looking better and globally, export orders have improved slightly. That said, it is too early to know whether this cautiously positive development will be sustained, as the global economy remains fragile."