Aero produced S-199.310. On May 30, 1949, this airplane, coded KT-3, made a forced landing not far from Boskovice while flown by rt. (Sgt) Karel Kessler. The code places the aircraft
in the service of the 3rd Flight of the Air Regiment 7. This S-199 was only armed with the synchronized 131/13N fuselage machine guns, lacking the wing gun pods. After necessary
repairs, the aircraft was updated with the rearward sliding bubble canopy and was equipped with reconnaissance equipment and reassigned to LP 1. In 1951, it served with the
5 Air Training Regiment in Zvolen, where it was coded UL-51 and obtained yellow training bands. It was likely that the reconnaissance equipment had been removed by that time.
White GY-37 was Avia S-199.40 (2nd Flight, 3 Fighter Air Regiment, 4 Air Division), and was already worn when it collided with the two-seat CS-199.510 (coded HX-70) at Černovice
airfield in Brno on March 23, 1953. It sported multiple repairs with a darker green, with which it became one of the most interestingly painted S-199s in the Czechoslovak Air Force.
In accordance with regulations from October 1947 (Avia Scheme Illustration for Type 210 “Stencil Data and National Markings” No. 109-Le62217), the aircraft carried a white border
line to the national markings. The spinner was also white.