The Eagle Squadron was made up from American volunteers and proved to be a formidable fighting force. Equipped firstly with Hurricanes, the squadron then used Spitfire Mk.IIs until being upgraded to the RAF's latest cannon equipped Spitfire Mk.Vb in late 1941. They were disbanded once America entered the war properly and its air arm arrived in England in 1942, with the Eagle Squadron personnel and machines being turned over to the fledgling Eighth Air Force.
William R. Dunn was the first American ace of the Second World War. First flying Hurricanes with 71 Squadron, he shot down his first enemy machines in July 1941, before becoming an ace flying Spitfires with the same unit in August. It was while flying this machine that Dunn was forced to land at Hawkinge, in Kent, after sustaining injuries to his leg in combat over occupied France.
After 3 months hospitalization and a further 3 months recovery William Dunn served as an instructor pilot in Canada and went on to lecture on air combat across various units in both Great Britain and the USA. He then joined the USAAF and flew combat missions again over occupied Europe, downing a Messerschmitt Bf110 in an unusual manner, with a salvo of 5 inch rockets.
Promoted to Captain and then Major after completing Command & General Staff College he was posted to China as commander of Luchien and Luchow Air Bases as Lieutenant Colonel, before assignment to Imperial Iranian Air Force to 1949. Dunn resigned his commission in November 1949, and rejoined in an enlisted capacity. As Chief Warrant Office Dunn served as a staff officer, Aircraft Controller, Interceptor Controller, Air Traffic Controller, and Wing Support Officer, Weapons Controller, staff officer Headquarters 29th Air Division, Weapons Controller, Weapons Officer on the staff of Headquarters Pacific Air Forces at Hickham, Hawaii, Weapons Force Plans Officer with the 6250th Support Squadron South Vietnam and finally Weapons Controller with Headquarters, Aerospace Defence Command. He was promoted to Chief Warrant Officer 4 in 1963, but retired at his highest rank held, that of Lieutenant Colnol. William Dunn died on the 14th of February 1995, and is buried at Fort Logan National Cemetery, Denver Colorado.
Dunn claimed 8.5 air victories, though was credited with 6 confirmed plus 4 unconfirmed, 3 probables, 4 damaged and 12 destroyed on the ground.