Heathrow Limited, owned by Spanish firm Ferrovial and formerly known as BAA, said 5.18m people used the UK’s busiest airport last month, up 0.3 per cent on a year ago.
Domestic travel fell 5.8 per cent but European and North American traffic have soared since the same period a year ago.
Heathrow’s load factor, which measures how full each flight is, rose 2.1 percentage points to 70 per cent. Cargo, however, fell 5.3 per cent on last year to 106,425 metric tonnes.
The positive figures follow a record year for Heathrow in 2012.
The airport will outline its spending plans for the five years to 2019 today, and is expected to earmark £3bn for upgrade work.
Meanwhile Gatwick, owned by private equity group Global Infrastructure Partners, saw a 0.8 per cent decline in passenger numbers to almost 2.1m passengers in January.
The airport said tough economic conditions and wintry weather both contributed to the slide.
Domestic traffic rose 2.7 per cent to 257,800 passengers, while non-US long haul flights gained 6.6 per cent to 413,300, helped by new routes to Korea, China and Russia.
European scheduled and charter flights both declined.