In 1956 a new runway was constructed, 07R/25L, which almost runs parallel with 07L/25R. The runway is still in use today and saw its length later increased to . In April 1956 the Belgian government decided to build a new airport, using the same runways, but with the buildings located within the municipality of Zaventem. In April 1957, construction started of the new terminal, preparing the airport for the 1958 World Fair. The grass runway 12/30 had to make way to allow for the new passenger terminal. This new airport was inaugurated 5 July 1958, almost just in time for the 1958 World Fair. The buildings on the Melsbroek side are still in use by the Belgian Air Force (15th Air Transport Wing), and this is still known as Melsbroek airfield. Both Zaventem Airport and Melsbroek Air Base, the military airfield, share the same runways.