The Palm Beach International Airport, then known as Morrison Field, opened in 1936. After the United States entered World War II, it was converted to an Air Force Base in 1942. During the war, thousands of servicemen arrived in Palm Beach County for training and supporting the war effort. Following the conclusion of World War II, a number of veterans returned to the area for work, vacation, or retirement. The base was closed and became a commercial airport again in 1962. Migration to the county by workers, tourists, and retirees continued into the 21st century.