SNOW disruption in other parts of the UK caused passenger numbers at Glasgow Airport to dip slightly in January.
Traffic figures show around 411,500 people travelled through the airport last month, which was 1.2% down on the same period last year.
However, Aberdeen International Airport posted its 24th consecutive month of growth, with the 228,900 passengers a 0.6% improvement on the 227,591 recorded in 2011.
Glasgow Airport's managing director Amanda McMillan said the site was still performing well and highlighted two new routes which will start next month.
She said: "Given the positive start we made to the year with the news 2012 had been our busiest year since 2009, it was frustrating to see passenger numbers take a slight dip as a result of poor weather conditions elsewhere.
"However, in terms of route development we continued to make significant progress, carrying on where we left off in 2012, with the announcement Wizz Air will operate flights to Warsaw and Gdansk from March.
"The addition of two major European cities to our list of destinations is particularly pleasing as was the decision by Flybe to introduce a year-round service to Shannon in the west coast of Ireland."
The Wizz Air flights transferred from Prestwick, leaving the Ayrshire airport, which is up for sale, with only one scheduled airline in Ryanair.
In recent weeks Glasgow has also added Tunisian tour operator Just Sunshine to its summer schedule and an additional Lufthansa route to Dusseldorf. Jet2 meanwhile is providing year-round flights to Rome and Barcelona.
In January more than 240,000 passengers using Glasgow were on domestic services, with continental Europe the next most popular destination on 120,949, and the Middle East in third position at 32,279 as the airport continues to benefit from its daily Emirates route to Dubai.
Overall passenger load factor at Glasgow was at 67.9%. The UK's worst performing area was at 61.7%. However, Glasgow saw its cargo performance almost double to 696 metric tonnes.
Aberdeen Airport said there was growth in both the domestic and European markets and it posted a load factor of 62.6%.
However, it warned a decline in helicopter flights were hitting traffic figures.
Several Super Puma helicopters were grounded following a ditching incident last October.
Some oil and gas firms have been using seagoing vessels to take workers to oil rigs in the North Sea.
Derek Provan, Aberdeen Airport managing director, said: "The ongoing issues with the helicopter fleet are having an impact on our figures, and we are working closely with all three operators to understand their respective operational issues.
"We had a positive year in 2012, and we are starting 2013 with further growth, however this set of figures reflects how challenging the market remains."
Cargo at Aberdeen was down 18.6% to 472 metric tonnes.
Heathrow Airport Holdings (HAH), which includes Southampton alongside Glasgow and Aberdeen in its portfolio, said passenger figures across the group were steady at 5.91 million in spite of the snow disruptions.
Southampton saw a 10.6% decline in the month to 88,200.
At Heathrow the number was up 0.3% to 5.18 million.
Without the disruption passenger growth would have been around 1.7% up.
The one spell of bad weather was estimated to have cost around 75,000 passengers at the London airport.