Dissatisfied with Hermann Göring's leadership of the Luftwaffe, Adolf Hitler wanted to replace him with Robert Ritter von Greim.

They refused to consider my arguments and tried to persuade me that Göring would not have countenanced any participation by the Armed Forces High Command in the affairs of the Luftwaffe, that he would have termed it interference and forbidden it.

To be sure, Göring was not a man to countenance interference, but he certainly would have welcomed constructive support and assistance from the Armed Forces High Command in improving the Luftwaffe's armament situation.

Hitler ordered Koller to send his remaining planes and airmen to assist in Felix Steiner's relief of Berlin and explained, "Any commander who holds back his forces will forfeit his life in five hours.

After Alfred Jodl told Koller that Hitler had decided to commit suicide, the Luftwaffe general flew to Obersalzberg at 3:30 a.m. on 23 April to inform Göring in person.

[10] In the ensuing power struggle between the Nazi leaders as Hitler's mental state declined, Martin Bormann sent SS troops to place Göring, Koller and Hans Lammers under house arrest at Obersalzberg.

In 1949 he published his wartime shorthand diary as the memoir Der letzte Monat (The Last Month, Mannheim), which provided information about Hitler's last days during the Battle of Berlin.