Steinbatz volunteered for military service in the Austrian Armed Forces in 1937. In March 1938, following the Anschluss, the annexation of Austria by Nazi Germany, Steinbatz was transferred to the Luftwaffe. Following flight training, he was posted to Jagdgeschwader 52 (JG 52—52nd Fighter Wing).
Steinbatz volunteered for military service in the Austrian Armed Forces in 1937. After Austria's incorporation into Nazi Germany in March 1938, Steinbatz was reassigned to the Luftwaffe and trained as a pilot before joining a fighter unit.