International Airlines Group, formed by the merger of BA and Iberia, posted a rise in passenger traffic for August thanks to continued growth in first-class and business-class travel.

Traffic, measured in revenue passenger kilometres, rose by 2.2 percent versus August 2010, while passenger load factor -- a measure of how well it fills its planes -- was up 0.1 percentage points at 84.9 percent.

Europe's second-biggest airline group by value behind Lufthansa said its first and business-class travel -- the most profitable part of its passenger business -- rose 8.7 percent, while non-premium traffic was up 1.4 percent.

Industry body IATA last week said it expected airlines to suffer a weak end to the year due to waning consumer confidence, sluggish international trade and high fuel prices.

IAG defied the gloom in the airline sector by posting a first-half profit in July and predicted full-year earnings growth, while its European rivals Air France and Lufthansa reported results battered by high fuel prices.

IAG shares in London were down 4.9 percent at 158.9 pence by 15:18 p.m. GMT, with the broader market down 3.7 percent. The Madrid-listed IAG shares were down 0.1 percent to EUR1.812.