Captain William James Arthur Duncan MC (July 4, 1891 – April 13, 1975) was a Canadian aviator and a professional ice hockey player, coach, and general manager.

In 1926 he served as the first team captain, head coach, and general manager of the Detroit Cougars of the National Hockey League (NHL).

He interrupted his sports career to serve in World War I, and became a fighter ace credited with 11 official aerial victories.

[1] Duncan scored his first aerial victory on November 6, 1917, when he destroyed a German DFW reconnaissance plane northeast of Polygon Wood.

On the day the RFC was consolidated into the Royal Air Force, April 1, 1918, he shared his seventh victory with American ace John Griffith.

[1] His combat exploits won him the award of the Military Cross, gazetted on July 26, 1918: For conspicuous gallantry and devotion to duty.

He then led his patrol over the enemy's lines, dived down to an altitude of 100 feet, and attacked large numbers of hostile infantry with machinegun fire, causing the utmost panic amongst them and inflicting heavy casualties.