Oslo Airport, Fornebu (IATA: FBU, ICAO: ENFB) (Norwegian: Oslo lufthavn, Fornebu), was the primary international airport serving Oslo and Eastern Norway from 1 June 1939 to 7 October 1998. It was then replaced by Oslo Airport, Gardermoen, and the area has since been redeveloped. The airport was located at Fornebu in Bærum, 8 km (5.0 mi) from the city center. Fornebu had two runways, one 2,370 m (7,780 ft) 06/24 and one 1,800 m (5,900 ft) 01/19, and a capacity of 20 aircraft. In 1996, the airport had 170,823 aircraft movements and 10,072,054 passengers. The airport served as a hub for Scandinavian Airlines System (SAS), Braathens SAFE and Widerøe. In 1996, they and 21 other airlines served 28 international destinations. Due to limited terminal and runway capacity, intercontinental and charter airlines used Gardermoen. The Royal Norwegian Air Force retained offices at Fornebu.

The airport opened as a combined sea and land airport, serving both domestic and international destinations. It replaced the land airport at Kjeller and the sea airport at Gressholmen. In 1940, it was taken over by the German Luftwaffe, but civilian air services began again in 1946 and it was then taken over by the Norwegian Civil Airport Administration. The airport at first had three runways, each at 800 m (2,600 ft), but these were gradually expanded, first the north–south runway and finally the east–west one to the current length in 1962. The same year the terminal moved south to the final location. A large-scale expansion to the terminal was made during the 1980s.