On 15 March, Swissair bought the A310. It said that it would buy 10 and have 10 options, to replace its McDonnell Douglas DC-9 series. Lufthansa bought ten planes for $240 million. Air France and Iberia soon did the same. On 1 April 1979 Lufthansa increased its order to 25 orders and 25 options. Two days later, KLM bought 10 planes and had 10 options, which cost ₤238 million. Other airlines which bought the A310 during 1979 included Martinair, Sabena and Air Afrique.