'Reinhard Heydrich - The Biography Vol.II/Enigma' by Max Williams:
'As soon as war had broken out, Heydrich was impatient to see active service.He obtained permission to fly as a Luftwaffe Reserve Officer with Bomber Group KG55 and first saw action on 12th September 1939 as a gunner.
(...) An ME 110 was also piloted by Heydrich, flying over England and Scotland on reconnaisance missions. During a mission in Norway, he over-flew a shot-up aircraft on landing and crashed, breaking his arm. Both Hitler and Himmler were aware of his sorties as an arm in plaster was difficult to conceal, but he was at pains to show them his duties as Chief of RSHA would not suffer as a result. In doing so, he kept from them the actual number of times he was engaged in skirmishes with the RAF.(...)
On Heydrich's return to SS duty, he was proudly sporting a newly awarded bronze combat mission bar on his left uniform breast.
(..)
Heydrich's next opportunity for aerial combat came during the Russian offensive. He flew numerous times over enemy territory and was engaged in several dogfights behind the lines. It was during one of these flights that he was forced to crash-land behind the Soviet lines, in the vicinity of Berezina. Eventually he was rescued by a German combat patrol. Lina Heydrich describes this incident as follows : "..Reinhard comes home, dirty, unshaven and very upset...He landed behind enemy lines, had hidden for two days and two nights and made his way on foot back to German units". (..) Heydrich was awarded the silver bar for combat missions and the Iron Cross First Class. Hitler noticed the new decorations and was horrified at the thought of his Security Chief being captured by the Russians. From then on, he was strictly forbidden to undertake such dangerous flights again. Luftwaffe Reserve Major Heydrich was grounded.'