Sabena served by the airline. Sabena used landplanes for its Congo operations and a program of aerodrome construction was initiated in the Congo. This was finished in 1926 and Sabena immediately began flights within the Belgian colony, the main route being Boma-Léopoldville-Élisabethville, a 2,288 km (1,422 mi) route over dense jungle. First, flights were operated with De Havilland DH.50s, although these were quickly replaced by the larger Handley Page W.8f which had three engines and offered ten seats. By 1931 Sabena's fleet, including the aircraft used on the Congo network, totalled 43 aircraft. Its mainstay type was the Fokker F.VIIB with
Alcazar (airline) Sabena. In addition, they had a strong tie with Northwest Airlines. In 1989, KLM bought 20 percent of the then ailing airline. In 1992, KLM had made a bailout purchase of Northwest, securing a 25 percent ownership of the airline, which is the maximum a foreign airline is allowed to own in a US airline. Swissair cooperated with Delta Air Lines and Singapore Airlines in a triangular cooperation, which was highly valued by the company's management. Delta was significantly larger than the other two US partner airlines, and had a base in New York City, rather than Northwest's hubs in