Reciprocal aid. An American crew at work on a British Halifax four-engined bomber evidence of the close cooperation between British and U.S. forces in Britain. U.S. ground technicians as well as fighter squadrons, are working with members of the Royal Air Force (RAF) and the Women's Auxiliary Air Force (WAAF) at many of the airfields which have been handed over to U.S. Army Air Forces under the British Reciprocal Aid Program