Following the U.S. entry into World War II, the Army Air Corps established a base in the Del Valle community on land once part of the Santiago del Valle Mexican land grant. The City of Austin purchased 3,000 acres to lease to the federal government for use as an air base, and construction began in May 1942 after the removal of homes, churches, and businesses. The first units of the 316th Troop Carrier Group arrived in late September, and the base served as a replacement center for the First Troop Carrier Command, training pilots to transport combat troops and supplies. In March 1943, it was renamed Bergstrom Army Air Field to honor Captain John August Earl Bergstrom, Austin's first casualty of war, who was killed at Clark Field in the Philippines on December 8, 1941, and in November 1943 the name was shortened to Bergstrom Field. Crews from Bergstrom served in the invasions of Normandy, southern France, Holland, and Germany. After the war, the air field became Bergstrom Air Force Base under the Continental Air Command, and planes from there participated in the Berlin Airlift in 1948-49. Over the next 50 years, Bergstrom served under both the Strategic Air Command and the Tactical Air Command, sending bombers and reconnaissance aircraft into combat theaters from Korea to Iraq. In 1968, the 12th Air Force moved its headquarters there to a newly completed circular building nicknamed the "Roundagon." Bergstrom Air Force Base closed in 1992 under the Base Realignment and Closure Commission, and the city converted it to Austin-Bergstrom International Airport in 1999.