 With the delivery of the Boeing 737 @-@ 200s , Braathens SAFE started using these aircraft on the long @-@ haul charter flights . By 1977 , there were nine international charter airlines competing with Braathens SAFE : <unk> , Britannia Airways , Dan @-@ Air , Linjeflyg , <unk> Air , <unk> ( owned by SAS ) , <unk> , Sterling and <unk> . In 1976 , good exchange rates gave a peak of flights to London , with eleven weekly flights across the North Sea . Braathens SAFE also started flying for <unk> . In 1976 , 44 % of the company 's revenue was from charter , but by 1979 it had dropped to 36 % . During this period , about half of the planes ' flying time was related to charter . 
