Heathrow owner BAA saw its March traffic rise by 0.9 per cent, buoyed by the increasing popularity of China and India as flight destinations.
The group, owned by Spanish infrastructure group Ferrovial, served 8.27m passengers, compared to 8.19m last March.
Heathrow accounted for the majority of its UK business, with 5.33m passengers, up 2.3 per cent year-on-year.
Heathrow to New York remains the world’s most popular transcontinental route, with 3.6m people flying to JFK and Newark airports – an average of one flight an hour.
However, Stansted saw a sharp drop year-on-year, falling 7.4 per cent, while Southampton fell 8.7 per cent.
BAA’s Scottish airports recorded a 5.8 per cent increase in traffic.
BAA chief executive Colin Matthews said: “The valuable trading connections to India and mainland China continue to see strong growth from Heathrow, which suggests improving economic circumstances and the increasing importance of these economies.”
Gatwick, which BAA was forced to sell in October 2009 to GIP, saw its traffic crawl up 1.4 per cent, just over half that of rival Heathrow.