WASHINGTON — The number of international air travelers flying in business or first-class fell in March by the largest amount in five years, the latest bad news for an industry buckling under record fuel prices and slowing global economies.

The International Air Transport Association yesterday said premium air traffic shrank 3.9 percent in March compared with the same month last year, after growing by 5.1 percent in February. Although the drop was exaggerated both by the leap year adding an extra day to February and because March business travel fell because of an early Easter, it was the largest "absolute decline" in business and first-class passengers since 2003.

"Given the importance of premium passengers for airline profitability the absolute decline in numbers is bad news, particularly since the price of jet fuel rose 170 percent over the year," IATA said.

Revenue did not fall as much as passenger numbers, since much of the weakness occurred in short-haul, lower-yielding markets, according to the trade group.

The results were not a surprise given the struggles of the U.S. economy and some others in southern Europe, but also do not bode well for an airline industry already stressed by record fuel prices.

Business travel is highly linked to the financial services sector, and many in that struggling industry have stopped flying, said IATA Chief Economist Brian Pearce.

"It will get worse before it gets better," Pearce said in a phone interview.

Large U.S. carriers have repeatedly raised ticket prices in recent weeks to offset surging fuel costs.

Raising fares and charging for extra bags and other amenities have been the preferred coping mechanisms for airlines paying about 86 percent more for jet-fuel than they did a year ago. Eleven of 15 airfare increase attempts by domestic carriers have been successful this year.