to German occupation. The successes confirmed Hitler's view that air power could be used politically, as a "terror weapon". In a series of meetings in Berlin, Hitler told Hácha that half of Prague could be destroyed in two hours, and hundreds of bombers were ready for the operation. Sperrle was asked by Hitler to talk about the Luftwaffe, to intimidate the Czech president. Hácha purportedly fainted, and when he regained consciousness, Göring screamed at him, "think of Prague!" The elderly President reluctantly ordered the Czechoslovakian Army not to resist. The aerial part of the German occupation of Czechoslovakia was carried out by 500–650 aircraft belonging to Sperrle's newly renamed air fleet, Luftflotte 3. The majority of these aircraft were concentrated in the 4 Fliegerdivision (4th Flying Division). The operational condition of the Luftwaffe was at 57 percent with 60 percent requiring maintenance, while depots had only enough replacement aero engines to cover 4 to 5 percent of frontline strength. Only 1,432 of the 2,577 aircrew available were fully trained. Just 27 percent of bomber crews were instrument trained. These problems effectively reduced fighter and bomber units to 83 and 32.5 percent of their strength. The Luftwaffe's saving grace was that the British, French and Czech air forces were in slightly worse condition in 1939. World War II On 1 September 1939, the Wehrmacht invaded Poland prompting the British Empire and France to declare war in her defence. Sperrle's Luftflotte 3 remained guarding German air space in western Germany and did not contribute to the German invasion, made possible by the non-aggression pact with the Soviet Union. The air fleet's Order of battle had been stripped of almost all of the combat units it held in March 1939. Only two reconnaissance staffel (squadrons) and a single bomber unit attached to Wekusta 51 remained. Sperrle received the competent Major General Maximilian Ritter von Pohl as his chief of staff. The two men made for a "good partnership". Sperrle was also assigned Major General Walter Surén, appointed as the air fleet's chief signals officer. Surén planned and organised the German field communications for the offensive in 1940. While guarding the Western Front during the Phoney War, Sperrle's small fleet of 306 aircraft—which included 33 obsolete Arado Ar 68s—fought off probing attacks of French and British aircraft. Sperrle developed a reputation as gourmet, whose private transport aircraft featured a refrigerator to keep his wines