X-Plane 10 Scenery--Polykastro And Hortero Airfield. These are two small airfields of Makedonia in Greece. Polykastro and Hortero in real life have no ICAO code because it is ZZZZ airports. Nonetheless here GX09 is the ICAO code for Polykastro and LGXO ICAO code for Hortero to make it easy find the airfields in X-Plane 10. By Vasilis - Maximos Sevastopoulos.