The Republic-Ford JB-2, also known as the Thunderbug, KGW and LTV-N-2 Loon, was a United States copy of the German V-1 flying bomb. Developed in 1944, and planned to be used in the United States invasion of Japan, the JB-2 was never used in combat. It was the most successful of the United States Army Air Forces Jet Bomb (JB) projects during World War II. Postwar, the JB-2 played a significant role in the development of more advanced surface-to-surface tactical missile systems such as the MGM-1 Matador and later MGM-13 Mace.

The 1st Proving Ground Group is a disbanded United States Army Air Forces unit. It was last active with the Army Air Forces Proving Ground Command, based at Eglin Field, Florida, where it was disbanded on 1 April 1944. The unit's personnel/equipment/mission was taken over by the 610th Army Air Forces Base Unit and 611th AAF Base Unit.