- Second World War (1939-1945)
- Oberleutnant (Flying Officer)
- Staffelkapitän 10. / Jagdgeschwader 11
- Awarded on:
- April 27th, 1945
Awarded for his wartime successes. These ultimately amounted to 39 aerial victories over the course of about 480 sorties. This latter total included 120 fighter-bomber sorties, in which Klein claimed 5 tanks destroyed.