The calculated distance (air line) between Klagenfurt am Wörthersee and Wels is approximately 107 miles respectively 173 kilometers.
By car or train, the actual journey to Wels is certainly longer, as only the direct route (as the crow flies) between Klagenfurt am Wörthersee and Wels has been calculated here.
Air line (approximately)
173 kilometers
93 nautical miles