Business air travel falls, economy class picks up

* Sept business-class traffic falls 13.9 pct on yr

* Asia flights fill more seats than Europe, North America

GENEVA Nov 17 (Reuters) - Demand for business and executive seats, the main driver of profitability for most airlines, fell in September despite an uptick in overall passenger numbers, global airlines body IATA said on Tuesday.

Air passengers bought 1.2 percent more tickets in September than the same month a year ago, but premium travel numbers dropped 13.9 percent, the International Air Transport Association said.

In its latest snapshot of the premium travel segment, IATA said shaky global trade volumes have caused businesses to cut back on travel -- especially within Europe and North America.

Business class demand was relatively stronger in much of Asia, excluding Japan, where economic growth is getting back on track, the Geneva-based industry group said.

"Further improvement in the wider economy will have to materialise to sustain the improvement in air travel numbers," IATA said, noting that many former first- and executive-class passengers are opting for lower=cost tickets in the downturn.

"There has been an increasing shift by business travellers from the front to the back of aircraft during the recession," it said. Economy travel is generally dominated by people on holiday and leisure trips, many of whom have taken advantage of cut-rate tickets in recent months.

IATA, whose 230 members include Cathay Pacific (0293.HK), Lufthansa (LHAG.DE), United Airlines UAUA.O and Emirates [EMIRA.UL], has said the global airline industry will lose $11 billion in 2009 as a result of the economic slowdown. (Reporting by Laura MacInnis; Editing by Erica Billingham)