Arct fought in the Polish armed forces until the fall of Poland at the beginning of World War II. He escaped to France and served as a flight instructor with the French Air Force in French North Africa. After France capitulated in June 1940, Arct flew to Great Britain and became a fighter pilot at the beginning of 1941, attending Royal Air Force (RAF) Operational Training Unit 61, and then joined the No. 306 Polish Fighter Squadron (RAF) in October 1941.