The calculated distance (air line) between Klagenfurt am Wörthersee and Pradl is approximately 143 miles respectively 231 kilometers.
By car or train, the actual journey to Pradl is certainly longer, as only the direct route (as the crow flies) between Klagenfurt am Wörthersee and Pradl has been calculated here.
Air line (approximately)
231 kilometers
124 nautical miles