Korean War two years of fighting became a war of attrition, with the front line close to the 38th parallel. The war in the air, however, was never a stalemate. North Korea was subject to a massive bombing campaign. Jet fighters confronted each other in air-to-air combat for the first time in history, and Soviet pilots covertly flew in defense of their communist allies. The fighting ended on 27 July 1953, when an armistice was signed. The agreement created the Korean Demilitarized Zone to separate North and South Korea, and allowed the return of prisoners. However, no peace treaty was ever signed,
Forward air control operations during the Korean War Forward air control operations during the Korean War Forward air controllers in the Korean War were prominent throughout the conflict. United Nations forces depended upon improvised U.S. forward air control systems. The United States military held two competing doctrines for directing close air support (CAS). The U.S. Marine Corps' system depended on an organic supporting air wing delivering ordnance within 1,000 yards of front-line troops; this was to compensate for their weakness in artillery caused by being an amphibious force. On the other hand, the U.S. Army believed close air support should extend the range of its own organic artillery;