Swiss International Air Lines made an operating profit of CHF146m in 2009 (£90.7m), with positive results recorded in all four quarters.
The operating profit was the CHF326 below what the airline made in 2008.
Swiss carried 13.8m passengers in 2009, a 2.4% increase on the 13.5 million flown the previous year.
Gregor Koncilja, Swiss' UK and Ireland country manager, said: "We are pleased to count ourselves as one of the few airlines to post a profit not only for 2009 but for all 4 quarters of the past year. This achievement allows us to continue to invest in our products and services."
Swiss launched a six-times daily flight from Heathrow to Geneva in January, and plans to increase capacity on its Manchester-Zurich route from April.
Koncilja said the LHR-GVA route has "picked up very well".
"I think it was the right moment to step in on that new route for us," he said.
He warned, however, that Heathrow was unlikely to see much expansion this year, with Swiss instead concentrating on its regional airports, Manchester and Birmingham.
"The traffic out of the London region has slightly declined because of the financial and banking sector. We'd rather move capacity into the regions. That's where we have seen substantial growth over 2009. It's all about capacity management," said Koncilja.
Yield management will also be a focus in coming months, he said, with the airline looking to reduce the number of cheaper tickets available on popular routes.
"That's the goal. As soon as the demand is there we can enforce it through upscale initiatives. We have a whole variety of booking classes, with rather small steps from one booking class to another... It depends on supply and demand." said Koncilja.