In later 1938, Redlich fought in the Spanish Civil War with Jagdgruppe 88, under the command of the Condor Legion, and claimed four aerial victories.

Ten days later on 29 May, Redlich was killed in action during aerial combat with United States Army Air Forces bombers over Sankt Pölten.

[1] In April 1934, he volunteered for military service in the Reichsmarine (German Navy), later renamed to Kriegsmarine, as an officer cadet.

[5] World War II in Europe began on Friday, 1 September 1939, when German forces invaded Poland.

On 1 October 1939, the new I. Gruppe (1st group) of Jagdgeschwader 27 (JG 27—27th Fighter Wing) was created at Münster-Handorf Airfield and placed under command of Hauptmann Helmut Riegel.

[6] On 22 January 1940, the Gruppe moved to Krefeld Airfield where they were tasked with flying fighter protection during the "Phoney War" along the German – Belgian border.

[8] The next day, Redlich claimed his first victory of World War II, a Fairey Battle light bomber shot down near Tongeren, probably belonging to the Belgian Air Force.

Staffel intercepted a Royal Air Force (RAF) Westland Lysander aerial reconnaissance aircraft, escorted by Hawker Hurricane fighters, in the area of Brussels and Charleroi.

Three days later, they were ordered to Saint-Omer for combat against the encircled Allied forces fighting in the Battle of Dunkirk.

[11] This claim earned him the Iron Cross 1st Class (Eisernes Kreuz erster Klasse) that day.

[12] When the Armistice of 22 June 1940 was signed, Redlich was credited with seven aerial victories and was one of the leading fighter pilots of I. Gruppe of JG 27.

[13] In preparation in what would become the Battle of Britain, I. Gruppe was moved to the English Channel on 2 July where they were based at an airfield near Plumetot.

[14] On 7 September 1940, I. Gruppe participated in Operation "Loge", 350 bombers escorted by 648 fighters, attacked various targets in the greater London area.

Again escorting Luftwaffe bombers to London, Redlich claimed his tenth aerial victory in total when he shot down a Hurricane near Sevenoaks.

Here the Gruppe was subordinated to the Geschwaderstab (headquarters unit) of Jagdgeschwader 1 (JG 1—1st Fighter Wing) and tasked with patrolling the German Bight.

[18] On 3 December 1940, I. Gruppe was again withdrawn from the English Channel and relocated to Döberitz located approximately 10 kilometers (6.2 miles) west of Staaken.

There, the ground crew began preparations for the air elements to arrive at the designated airfield at Ayn al-Ġazāla.

The orders for I. Gruppe that day were to attack and destroy the Yugoslavian air defenses in the area of Laibach, present-day Ljubljana in Slovenia.

[21] Following Operation Marita, the air elements briefly returned to Munich-Riem before they transferred to North Africa, arriving in Ayn al-Ġazāla between 18 and 22 April 1941.

[32][33] On 29 May 1944, the United States Army Air Forces (USAAF) targeted German aircraft production and Luftwaffe infrastructure.

At the same time, the USAAF Fifteenth Air Force attacked the Wiener Neustädter Flugzeugwerke [de], manufacturing at Atzgersdorf, and the airfield at Wollersdorf, with 563 heavy bombers.

In the area of Sankt Pölten, the Gruppe under the leadership of Redlich intercepted a formation of Consolidated B-24 Liberator bombers.

[35] Redlich was buried in the war grave section of the Main Cemetery Sankt Pölten [de] (Block 3–Row 7–Grave 202).

[38] The authors Ring and Girbig list Redlich with 43 aerial victories which includes one four-engined heavy bomber.