BAA’s six airports handled 7.1 million passengers in February, down by a marginal 0.2% on the same month last year.
But the airports operator said it was concerned about the impact of planned rises in Air Passenger Duty.
Heathrow and the company’s Scottish airports all showed increases last month but traffic fell by 6.3% at Stansted as budget airlines shifted aircraft to the Continent and 9.5% at Southampton due to a decline in domestic travel.
Heathrow’s traffic grew by 0.5% in February, with good performance on European scheduled services in what is traditionally the quietest month of the year, BAA said.
European scheduled traffic grew most strongly across BAA airports (up 1.4%) but there were falls in domestic traffic (down 2%) and North Atlantic traffic (down 1.5%). Other long haul routes were up by 0.6% overall, including increases of nearly 10% on Indian services from Heathrow.
The steady growth in demand at Heathrow suggests improving economic circumstances, the company said.
Chief executive Colin Matthews said: “We remain focused on improving the service we offer passengers and airlines at all our airports.
“Heathrow’s strong passenger and freight performance is encouraging for British industry, reflecting steady improvements in the economy and international trade.
“At our other airports, the slow pace of economic recovery is impacting growth.
“Looking ahead, we remain concerned that increases in Air Passenger Duty planned by the government will affect the relative competitiveness of UK aviation and damage the UK’s international trading position.
“Aviation plays an important role in promoting economic growth and the industry should not be treated simply as a source of revenue.”