Closest airport is WRO - Wroclaw. About 2 hours drive to Zieleniec.
Other option is to fly to PRG - Prague - about 3hours drive to Zieleniec.
you can get with a train or bus to Duszniki Zdrój.
Contact us and we can organize a pick-up or you can take a taxi that will take you to Zieleniec (10min drive)