Plans for the construction of a joint Swiss–French airport started in the 1930s, but were halted by the Second World War. Swiss planners identified Basel as one of the four cities for which a main urban airport would be developed, but recognized that the existing airfield at Sternenfeld in Birsfelden was too small and, due development of the adjacent river port facilities, unsuitable for expansion. The suburb of Allschwil was proposed for a new airport, but this would require being constructed across the Franco-Swiss border, leading to talks with French authorities centered developing a single airport that would serve both countries, enhancing its international airport status.