The first airports appeared in Islay in the 1930s. However, these were just grass strips. In 1940, during World War II, the British Prime Minister, Winston Churchill ordered military airports to be constructed in the western islands of Scotland, both to defend against a German assault on the Scottish mainland and also to provide reconnaissance planes a base to fly missions over the Atlantic Ocean. The present Islay airport was constructed as RAF Port Ellen in 1940, and received a concrete runway in 1942. During World War II, over 1,500 Royal Air Force (RAF) personnel were stationed at RAF Port Ellen.