The Airfield at Narsarsuaq was first built by The American Department of Defense (then known as the War Department) as an army airbase. Construction began in July 1941, and the first aircraft landed in January 1942. The airbase with the code name "Bluie West One" had during World War II squadrons of PBY Catalinas and B-25 Mitchells with the assignment to escort allied convoys and track and destroy German submarines. A military hospital with 250 beds was completed in 1943, and during World War II the population was approximately 4,000 people. It is estimated, that during the war more than 10,000 aircraft were ferried through the Narsarsuaq Airport.