 Braathens bought six Herons , in addition to one that was leased during 1954 . They had been given the common Norwegian names Per , <unk> , <unk> and Lars . Because of replacements , the airline never operated more than four at a time . In June 1955 , Braathens SAFE started landing some of the Oslo – Stavanger planes at Kristiansand Airport , <unk> and Farsund Airport , <unk> . The route , nicknamed the " Milk Route " , operated Stavanger – Farsund – Kristiansand – Tønsberg – Oslo in the morning , with a return in the evening . The same year , SAS and Braathens SAFE started negotiating splitting up the domestic routes . Nils Langhelle , then regional director in SAS , suggested creating a merged subsidiary that could fly all domestic routes . On 16 May 1956 , Braathens SAFE started landing at Hamar Airport , <unk> on the Oslo – Trondheim route , and at <unk> Airport , <unk> on the Oslo – Stavanger route . Both airports had 1 @,@ 000 metres ( 3 @,@ 300 ft ) runways that could only be served by small aircraft such as the Heron . From 1959 , services to both airports were terminated . Røros Airport was opened on 19 July 1957 , and Braathens SAFE landed some of the Oslo – Trondheim services there . After 1958 , services were terminated , but after the runway was extended from 1 @,@ 360 to 1 @,@ 600 metres ( 4 @,@ 460 to 5 @,@ 250 ft ) , it was taken into use again in 1963 . 
