BOC Aviation, Asia's biggest plane- leasing company, said the risk of airlines returning aircraft may increase this year as global travel growth slows.

"When we get to the end of the summer period that is the dangerous time for the market, when the northern hemisphere high-traffic period comes to an end,'' BOC Aviation's Chief Executive Officer Robert Martin said in a Bloomberg Television interview in Singapore broadcast today. "There's no doubt we're seeing some slowdown in the growth in the market.''

The collapse of more than a dozen carriers in the past six months because of higher jet fuel prices could idle planes leased out by rental companies and depress rates. An economic slowdown in the U.S., higher fares and inflation may crimp air travel and lead to a shut down of more airlines, said Jim Eckes, managing director of Indoswiss Aviation.

"Some start-up airlines are going to encounter serious trouble and won't survive in this current environment,'' said Eckes. "Looking at airlines that are already well established, some are in very poor financial conditions and will probably go under.''

Skybus Air

Of BOC Aviation's customers, only Ohio-based Skybus Airlines Inc. has filed for bankruptcy and ceased operations. BOC Aviation has taken over the sale and leaseback contract from the U.S. low-fare carrier for 17 aircraft, two of which have been recently leased to CSA Czech Airlines, Martin said.

A drop in air travel is more pronounced among discretionary travelers, who tend to buy cheap tickets, Steven Udvar-Hazy, chief executive officer of International Lease Finance Corp., the world's largest aircraft buyer, said in a June interview.

Budget carriers PT Adam Skyconnection Airlines and Oasis Hong Kong Airlines Ltd. ceased operations this year as jet fuel in Singapore trading have risen by 50 percent so far this year.

Qantas Airways Ltd., China Southern Airlines Co. and other Asia-Pacific carriers have said they plan to axe routes as they struggle to cope with jet-fuel prices that have almost doubled in the past year. Higher jet kerosene costs may push the industry toward its biggest global loss since 2003, the International Air Transport Association said.

As airlines keep raising ticket levies to help counter higher fuel costs, demand may slow among business travelers, who pay a premium for tickets, he added.

BOC Aviation owns and manages 82 aircraft, about 80 percent of which are single-aisle planes. The Singapore-based company has another 73 planes on order, according to its Web site.