UK airports group BAA has reported a 1.4% dip in March's passenger numbers compared with a year ago, after heavy snow led to cancelled flights.
Heathrow has seen user numbers dip over the past year
BAA, which owns seven UK airports, said that the late timing of Easter this year had also contributed to the fall.
For the year to March, Heathrow airport saw passenger numbers fall 0.3% to 67.4 million, which BAA blamed on July's bombs and the strike by catering staff.
Last week, BAA rejected a £8.75bn takeover bid from a Spanish consortium.
The consortium is headed by construction firm Ferrovial, and also includes Canadian investment fund Caisse de Depot et Placement du Quebec, and Singapore government fund GIC.
BAA said that domestic traffic during March was hit by cancellations caused by heavy snow at the beginning of the month in Scotland and the North East.
However, for the year to the end of March, BAA said that overall passenger numbers at its seven UK airports had risen by 2% to 144.6 million.
Gatwick saw 32.8 million passengers pass through the airport, the highest yearly figures to date.
The continued popularity of low-cost travel helped to lift numbers at Stansted, which saw a 5% rise in passengers to 22.2 million over the year to March.
Southampton airport saw user numbers jump 5.2% in March on a year ago, and for the year as a whole they were up 20.1% to 1.9 million.
In Scotland, Aberdeen airport recorded a 9.5% increase in passengers over the past 12 months, while numbers were up 2.4% at Glasgow and 5.6% at Edinburgh.