It was largely made up of newly trained soldiers and was to begin with characterized with a lack of experience in management and operations. Within a year it had twelve aircraft. Training was conducted at the Marka field outside Lista Air Station. Aircraft were flown home from the United Kingdom via RAF Gütersloh in West Germany. This base was also regularly used for international training. The 337 Squadron also participated in an international exercise at RAF North Weald. One aircraft crashed after a mid-air collision over Enebakk in 1950. Three aircraft were written off and one pilot killed in late 1951 at or near Gardermoen. Two aircraft collided over Nesodden the following year. The squadron received two Vampire trainers in late 1952. The 337 Squadron gradually received more missions in Northern Norway. With the delivery of new Republic F-84 Thunderjets to the 336 Squadron, the remaining Mk 3 Vampires were transferred to the 337 Squadron in 1952. From 1 November the squadron was given responsibility for air defence in Northern Norway. A detachment was stationed Bardufoss Air Station. It had at any given time about six to eight Vampires. The detachment suffered six write-offs and fatal accidents. Between 17 and 27 April 1953 the squadron was relocated to Værnes Air Station and became subordinate Air Command Trøndelag. Shooting training took place at Tautra, which opened in May of that year. There were two accidents that summer, one which was fatal. The unit participated in an exercise during the summer, when it was temporary located at Tønsberg Airport, Jarlsberg. In most of September 1954 the squadron was placed at Bardufoss for training. The Vampires were taken out of active service from late 1954. From 1 January 1955 the squadron was dedicated as a storage unit, relocated to Gardermoen and made responsible for storing 42 Vampires and 49 other aircraft of a wide range of obsolete models. Nearly all staff of the squadron was relocated, anticipating the arrival of the North American F-86K Sabre. The reactivation took place on 1 September 1955 and the first Sabre landed at Gardermoen twelve days later. Training was initially carried out with the Lockheed T-33A. The first F-86K was airborne on 1 November. The Sabres were intended for defence against possible Soviet attacks, using ground-controlled interception. They were all-weather fighters and advanced compared to the air force's other fighters. The 337 Squadron was therefore manned with experienced fighter crews.