After re-equipping with Bf 109Es diverted from the Luftwaffe, on 27 October the 13th Flight was deployed to the Eastern Front, where it was attached to the German fighter Geschwader, Jagdgeschwader 52, becoming its 13th Staffel, or 13.
As these aircraft were on loan, they retained standard German markings, distinguished by white, red and blue propeller spinners.
[4] The Slovak unit, which was suffering from poor morale, was withdrawn back to Slovakia in October 1943, leaving the Luftwaffe-owned Bf 109Fs and Gs with JG 52.
The 13th Fighter Flight was equipped with a mixture of Bf 109Es and Avia B-534s on its return to Slovakia, where it was based at Vajnory and then Piešťany, tasked with the defense of Bratislava.
[6] It re-equipped with factory-fresh Bf 109G-6s in early 1944,[6] operating under the control of the Jagdfliegerführer Ostmark (Fighter Leader Austria).