World War II in Europe began on Friday, 1 September 1939, when German forces invaded Poland. Fliegel flew combat missions over Poland and received the Iron Cross2nd Class on 15 September 1939. In early May 1940 when I. Gruppe of Kampfgeschwader 40, a unit equipped with the long-range Focke-Wulf Fw 200 "Condor"reconnaissance and anti-shipping/maritime patrol bomber aircraft, Fliegel was transferred to the 2. Staffel of KG 40. The unit initially operated against enemy shipping from airbases in Denmark. There he was awarded the Iron Cross 1st Class on 13 May 1940. In mid-1940, I. Gruppe relocated to the airbase Bordeaux-Mérignac at the Atlantic coast near Bordeaux in France. In October 1940, he was appointed Staffelkapitän of 2. Staffel of KG 40. Flying the Fw 200 to its maximum range, I. Gruppe was credited with the destruction of 39 enemy merchant ships totaling, further damaging 20 ships of. On 6 February 1941, under the command of KapitänleutnantNicolai Clausen, spotted convoy HG 53, 19 merchant ships escorted by and, heading for Liverpool. Clausen reported the sighting, which was relayed to KG 40 by Fliegerführer Atlantik. On 9 February, KG 40 sent five Fw 200s to attack the convoy which was spotted at 4 pm roughly southwest of Lisbon. In the attack at, the Fw 200's managed to sink five ships, and Deptford damaged the Fw 200 piloted by Oberleutnant Erich Adam, who managed to fly his aircraft to Spain. U-37 sank three further ships from HG 53. This achievement earned him his first mention in the Wehrmachtbericht, an information bulletin and element ofNazi propaganda issued by the headquarters of the Wehrmacht. Fliegel was awarded the Knight's Cross of the Iron Cross on 25 March 1941. In mid-April 1941 he was appointed Gruppenkommandeur of I. Gruppe of KG 40, replacing Major Edgar Petersen. He was mentioned a second time in the Wehrmachtbericht on 20 June 1941 after the number of enemy shipping destroyed by his Gruppe increased by a further 24 ships, reaching 109 enemy ships sunk. By early 1941 I. Gruppe of KG 40 had five holders of the Knight's Cross of the Iron Cross reflecting the success of the Condors in Atlantic Ocean operations.
Killed in action
On 18 July 1941, Fliegel and his crew—copilot Leutnant Wolf-Dietrich Kadelke, first radio operatorOberfeldwebel Johannes Rottke, second radio operator Gefreiter Karl Becker, flight engineerUnteroffizier Johann Kothe and air gunnerUnteroffizier Karl Meurer—were reported missing in action over the Atlantic in the vicinity northwest of Ireland. Their Fw 200 C-3 "F8+AB" was shot down in an attack on convoy OB 346. During the attack on the freighter Pilar de Larrinaga, the gunners onboard the freighter scored a hit on the Fw 200's starboard wing which tore it off. At the time of his death, Fliegel was credited with seven ships sunk plus further six damaged. He was promoted to Major posthumously.
Awards
Iron Cross
* 2nd Class
* 1st Class
Knight's Cross of the Iron Cross on 25 March 1941 as Hauptmann and Gruppenkommandeur of the I./Kampfgeschwader 40