The U.S. Army leased the Dover public airport within ten days of Pearl Harbor (December 7, 1941) and created Dover Army Air Field, today a 3,900-acre facility. Fighter pilots trained here. Building 1301—a combination of hangar, heating plant, and shop—housed top-secret facilities for testing air-launched rockets. The 155

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160–foot hangar stands forty-two feet high, the steel truss roof system supported by concrete buttresses.