The calculated distance (air line) between Klagenfurt am Wörthersee and Hernals is approximately 144 miles respectively 232 kilometers.
By car or train, the actual journey to Hernals is certainly longer, as only the direct route (as the crow flies) between Klagenfurt am Wörthersee and Hernals has been calculated here.
Air line (approximately)
232 kilometers
125 nautical miles