William Reid, the son of a blacksmith, was born on 21 December 1921 in Glasgow, Scotland. After completing school, he volunteered to serve with the Royal Air Force (RAF) and was sent to Canada, where he received flight training in the British Commonwealth Air Training Plan (BCATP). The BCATP trained thousands of air crews for service in World War II, which began in 1939. In 1942, Reid was commissioned and sent to an operational training unit in England's Midlands. He appeared to be a natural pilot and was chosen to serve as an instructor pilot on bombers, particularly Vickers Wellington medium bombers. In July 1943, Reid was sent to a conversion unit, where he received training on the Avro Lancaster heavy bomber. Two months later, he was transferred to 61 Squadron, an operational Lancaster unit.
With 61 Squadron, Reid flew several missions over Germany. On the night of 3 November, he participated in a raid on Dusseldorf, located near Germany's western border. On the way to the target, Reid's Lancaster was attacked from the front by an enemy Messerschmitt Bf-109 fighter. The bomber's cockpit and rear turret were damaged and Reid was badly wounded. Still, he continued with the mission. Soon, another fighter, this time a Focke-Wulf FW-190, attacked Reid's aircraft, killing his navigator, fatally wounding his wireless operator and wounding his flight engineer. Reid received more wounds and his aircraft was damaged to an even greater extent. The cockpit windows had been shattered and Reid was bleeding profusely from wounds on his body and face, but he accurately dropped the Lancaster's bombs on the target, before nursing the stricken bomber towards England. A hand pump had to be used to lower the Lancaster's landing gear, which collapsed upon touchdown. The aircraft slid down the runway, eventually coming to a halt, with Reid and most of his crew members surviving the mission. For his bravery, Reid was awarded a Victoria Cross (VC), the British Commonwealth's highest military decoration.
Reid's VC citation read, in part, "Flight Lieutenant Reid refused to be turned from his objective and Dusseldorf was reached some 50 minutes later. He had memorised his course to the target and had continued in such a normal manner that the bomb-aimer, who was cut off by the failure of the communications system, knew nothing of his captain's injuries or of the casualties to his comrades. Photographs show that, when the bombs were released, the aircraft was right over the centre of the target. Steering by the pole star and the moon, Flight Lieutenant Reid then set course for home. He was growing weak from loss of blood. The emergency oxygen supply had given out. With the windscreen shattered, the cold was intense. He lapsed into semi consciousness. The flight engineer, with some help from the bomb-aimer, kept the Lancaster in the air despite heavy enemy anti-aircraft fire over the Dutch coast. The North Sea crossing was accomplished. An airfield was sighted. The captain revived, resumed control and made ready to land. Ground mist partially obscured the runway lights. The captain was also much bothered by blood from his head wound getting into his eyes. However, Reid made a safe landing although one leg of the damaged undercarriage collapsed when the load came on. His tenacity and devotion to duty were beyond praise."