Liquid takes over from the incumbent Fox Kalomaski, with Red Cell Response and Proximity also understood to have taken part in the pitch process.
The appointment follows Liquid being hired by SAS to work on the group's business class travel account.
SAS was originally looking at hiring separate agencies to work on its DM business and leisure accounts, however Liquid was asked to pitch for the second account, believed to be worth 拢1m.
Chris Boddice, director of Liquid, said: "The group is seen as Scandinavia's flagship airline brand and has a great reputation, but the airline hadn't really done much promotion since it launched its new product so the campaign aims to drive awareness and improve customer relationships."
The agency, which launched a specialist data division Liquid Mind in March, is due to launch its first campaign for the airline to the business market in a couple of weeks' time as a "teaser" campaign, with follow-up work continuing to the rest of the year.
Liquid will develop the campaign across direct response press, radio online, events, direct marketing and sales promotion.
The campaign follows a revamp of SAS's operation, which saw it move away from a first-class business and economy service to a new product mix of business and leisure, focusing on weekend breaks and top business class travel.
At the end of 2004, it launched its business class, economy flex and economy service to compete with low-cost airlines such as EasyJet and Ryanair and the weekend break market.
SAS was formed by the merger of three Scandinavian airlines. The Swedish government owns 21% of the company with the governments of Denmark and Norway each owning 14%.
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