In 1936, he made a record-breaking flight to Khabarovsk, in the Far East, in 54 hours and 13 minutes, to deliver an engineer and spare parts to the famous Soviet pilot, Valery Chkalov, who had damaged his plane in an accident.

Proskurov was appointed head of Soviet military intelligence, the GRU, and deputy USSR People's Commissar for Defence, on 14 April 1939.

After the Finnish debacle, when the Military Council met in April, Proskurov refused to accept Stalin's line that poor intelligence was to blame.

[3] Proskurov sent the first report to Stalin, Vyacheslav Molotov and Marshal Timoshenko on 6 June 1940, warning that as soon as France had been forced to capitulate, the Germans would begin preparing an invasion of the USSR.

On 4 April 1941, Stalin sent Timoshenko a note directing that Proskurov be arrested, but the decision was delayed, and on 19 June he was appointed commander of the air forces of the Seventh Army.