Budget carrier Norwegian Air posted smaller than expected passenger growth in December and recorded additional losses from fuel hedging positions, its monthly traffic report shows. 

Norwegian, which has been courted by Aer Lingus and British Airways owner IAG, has rapidly expanded its transatlantic business in recent years but has struggled to turn a profit amid tough competition. 

While the airline's capacity grew by 34% year-on-year in December, revenue-generating passenger kilometres increased by only 24%.

This lagged a forecast of 32.9% in a Reuters poll of analysts.