Edinburgh Airport saw a 3.4% drop in international traffic last month following the sale by BAA, but the new owner said it was confident it would return to growth in 2013.
A total of 580,772 passengers travelled through the airport in December, an overall drop of 1.8% compared to the previous year.
Domestic passenger numbers fell by 0.6%.
Global Infrastructure Partners, the owner of Gatwick and London City Airports, bought Edinburgh Airport from BAA last spring for about £800m.
Edinburgh Airport chief executive Gordon Dewar said: "2012 was a challenging year for Edinburgh Airport. It’s clear that we lost some momentum at the beginning of the year due to the sales process and the last months of BAA ownership.
"However, I’m delighted that with the work done on new route development since the airport was purchased by GIP, 2013 will see us offer Scottish passengers over 130 routes in 2013.
"Clearly, I wish to see this figure grow, but it’s a fantastic start to the year given what we’ve been through.
"New routes from easyJet, Ryanair, Air Canada and Virgin Atlantic all mean that we will be offering our passengers more choice than ever before."
