By Laura MacInnis
GENEVA, Jan 30 (Reuters) - Air cargo traffic is likely to keep weakening in the next six months, reflecting a darkening global trade and business picture, a global airport industry body said on Friday.
The Airports Council International (ACI) said the global economic downturn pushed overall freight shipments 20 percent lower in December. International traffic was down 25 percent and domestic traffic 9 percent from the same month of 2007.
Its December reading was slightly weaker than those released on Thursday from the International Air Transport Association (IATA), which said cross-border air freight traffic fell 22.6 percent in the month. IATA figures exclude domestic flights.
"Further deterioration in the air freight sector can be expected over the next two quarters, reflecting the constricted global trade and commerce environment in which we are operating," said ACI World Director General Angela Gittens.
Falling freight shipments are bad news for the global economy -- in value terms, a third of world trade is in goods sent by air.
"An overall contraction in 2009 is inevitable," Gittens said in a statement, saying it could be as much as minus four percent. Last year had been "a turbulent and sobering year for the airport industry", she said.
For 2008 as a whole, the Geneva-based airports body said preliminary figures show worldwide air passenger traffic was nearly flat, declining 0.6 percent from 2007, which ACI had called a "banner year" for the airline industry.
Worldwide freight traffic was an estimated 4.3 percent lower in 2008. Strong demand at the start of the year helped cushion the blow from economic and financial turmoil that took hold in September and is set to continue through 2009, said ACI, whose members operate 1,679 airports in 177 countries.
In December 2008, the number of people travelling by air worldwide fell 6 percent compared to the same month the year before, with many of the world's top airports logging traffic declines, ACI said.
Bangkok's airport, where flights were blockaded during a week-long siege by protesters from Nov. 25, saw traffic fall 42 percent in December, while London Gatwick had a 14 percent decline, Seoul's Incheon saw 13 percent less traffic and Tokyo's Narita airport had 10 percent fewer travellers.
Dubai was an exception, with a 5 percent rise in the month. Global airlines are set to post $2.5 billion in losses in 2009 after suffering a $5 billion loss last year, according to figures from IATA. (Editing by Stephanie Nebehay and Mark Trevelyan)