June 6,1944 Operation Overlord, the Normandy invasion - like William the Conqueror's before it or the Inchon landing afterwards - will long be studied as a classic in military planning, logistics, and operations. Overlord depended to a remarkable degree upon the use of air power in virtually all its forms. A half-century ago, aircraft were primitive vehicles of war compared to the modern attackers of the Gulf War era, with their precision weapons, advanced navigational, sensor systems, and communications. Yet, the airplane still had a profound impact upon the success of the invasion. Simply stated, without air power, Normandy would have been impossible.