SINGAPORE — Improved efficiency has helped airlines better prepare for a possible global economic slowdown compared to the last major recession, but expensive fuel continues to hurt bottom lines, an airline industry group said yesterday.

The airlines "are better prepared because we have a much more efficient system overall," the International Air Transport Association's chief executive, Giovanni Bisignani, said on the sidelines of the Aviation Leadership Summit in Singapore.

"Simplifying businesses brings in to the industry $6 billion in savings. We've been able to develop new routes and (improve) fuel efficiency," Bisignani said.

Since 2001, the industry has seen labor productivity rise 64 percent, while nonfuel unit costs have dropped 16 percent and sales and marketing costs have decreased by 25 percent, according to the association.

Bisignani said, however, it is still too early to forecast the impact on airlines' revenues that a U.S. or global slowdown would have and warned that tough times were ahead.

"The revenue cycle peaked in 2006 and the negative impact of the credit crunch is still being calculated. Airlines may be out of intensive care but the industry is still sick," he said earlier in an opening speech. The association expects air-traffic growth to slow from 5.9 percent in 2007 to 4 percent this year.

High oil prices are somewhat offsetting gains made in improving efficiency, Bisignani added.

He said the bill for oil spending this year was likely to be about $150 billion, based on an estimated price of oil at $78 a barrel. Fuel makes up nearly 30 percent of the total operating cost of an airline, he said.

"Just imagine in 2003, our bill was $44 billion. ... You see how the impact has changed?" he said.

Carriers also are in a more vulnerable position now than during the 2001 recession because of mounting debt, which could see airlines headed toward an economic downturn with little cash to mitigate the fall, Bisignani said.

Airlines said they were thinking of ways to cope with a potential slowdown in the world economy that could affect air traffic.

"The probability (of a slowdown) has gone up a lot since the turn of the calendar year," said Singapore Airlines Chief Executive Chew Choon Seng.