Aircraft Warning Service  The Aircraft Warning Service (AWS) was a civilian service of the United States Army Ground Observer Corps instated during World War II to keep watch for enemy planes entering American airspace. It became inactive on May 29, 1944. During World War I, the airplane was not generally used as a long-range fighting machine. However, during the period from 1919 to the start of World War II, the heavy bomber was created, capable of ranging far from its home base and carrying a lethal load of high explosives. It soon became clear that a warning system was needed to protect against this new threat. Technology at the outset of World War II consisted of mechanical sound detectors that were found to be inadequate to the job. It was also argued that while soldier lookouts would be valuable, their use would detract from other needed military operations. The answer was found in calling on civilian volunteers to act as airplane spotters. With the help of the American Legion, volunteers were organized in May 1941 into the Aircraft Warning Service, the civilian arm of the Army's Ground Observer Corps. On the east coast, the AWS was under the auspices of the Army Air Force's 1st Interceptor Command (later First Fighter Command or I Fighter Command) based at Mitchel Field, New York. On the west coast, the AWS was under the auspices of the 4th Interceptor Command (later Fourth Fighter Command or IV Fighter Command) based in Riverside, California. On both coasts, observation posts, information centers and filter centers were established. The United States entered World War II on Dec 7, 1941. Many of those who could not join the military for whatever reason were recruited to the AWS. Statistically, this led to a preponderance of women, apparent in the surviving material, but seemingly little recognized. All observers received extensive training in aircraft recognition. This training was so successful that it spilled over into the non-AWS population. Aircraft recognition became a significant hobby providing many with thousands of hours of entertainment and spawning many books and publications, including flashcards, on the subject. Many participated in contests and recognition "Bees". Recognition clubs and meeting flourished becoming a major social phenomenon of the day. Of significant note to the training effort was the use of black, hard rubber, spotter models for various aircraft. Today, often mistaken for poor quality toys, these models can be worth hundreds of dollars and need to be preserved as part of AWS history. As the war escalated, thousands of observation posts were established on the east coast from the top of Maine to the tip of Florida, and roughly inland as far as the western slopes of the Appalachian Mountains.