 Complete the following phrase:  Following the surrender of the Royal Yugoslav Army on 17 April 1941, while stationed at an airfield at Zemun near Belgrade, the Geschwader received orders on 3 May 1941 to turn over all Bf 109-Es so they could receive the new Bf 109-F variant. Transition training was completed at Airfield Stolp-Reitz in Pomerania. Following intensive training, the Geschwader was moved to airfields in Eastern Prussia. On 22 June at 03:05, 120 aircraft of the Geschwader crossed into Soviet airspace in support of 