Passenger numbers at BAA's five UK airports declined 2% year-on-year to 9.52 million in August, while total aircraft movements fell 0.5% to 73,500.
Among its London airports, Heathhrow saw a 1.9% decrease in passenger numbers to 6.46 million, while at Stansted footfall was down 5.2% to 1.88 million.
Both the London gateways saw a fall in aircraft movements, with Heathrow and Stansted posting a 0.3% and 4.4% decline respectively.
Among its other UK airports, Southampton posted a 6.4% decline in passenger numbers, while Glasgow and Aberdeen witnessed increases of 3.1% and 9.2% respectively.
Glasgow and Aberdeen saw an increase in aircraft movements of 2.4% and 5.1% respectively, while Southampton posted a decline of 6.3%.
Total cargo at BAA's five airports increased 2.6% to 142,000t, with Heathrow contributing the lion's share at 121,000t. Glasgow saw the highest proportional increase - up fourfold to 730t.