During World War II, British officials were increasingly concerned with the large-scale need to maintain and repair the Royal Air Force's American-built aircraft. In April 1942, the U.S. Army Air Forces (USAAF) chose the existing Burtonwood Repair Depot (BRD) in England to be used as a centralized repair facility until the Eighth Air Force firmly established itself in the United Kingdom. The depot was subsequently transferred to American management, where it would be known as the 401st Air Depot, AAF Station 590. By July 1942, orders for the creation of a civilian service detachment reached the San Antonio Air Depot at Duncan Field (which consolidated with Kelly Field in 1943). Volunteers were sought to create a balanced team of aircraft specialists with a comprehensive mix of skills that could operate a repair depot facility. The 1,050 volunteers accepted were not told where their overseas station would be located. The site would be known as Station "X." The civilians, primarily Texans, left in four groups over five months, sailing across the U-boat-infested Atlantic Ocean and sent to Warrington, England, near BRD. They were soon working overtime with British civilians and eventually USAAF personnel. During the war, over 3,368 aero engines and 11,757 aircraft including 4,243 B-17 Flying Fortress bombers, 4,381 P-47 Thunderbolt fighters and 1,004 P-38 lightning fighters were modified or overhauled. As the number of American military technicians increased by 1944, civilians of Station "X" began returning home, with some staying in England until 1945. Many went on to serve in the armed forces for the rest of the war. Their devotion to duty in keeping allied planes airborne during a crucial and vulnerable time of the war is best exemplified in their motto: "Keep 'Em Flying" (2018)