The calculated distance (air line) between Saint-Josse-ten-Noode and Aalst is approximately 16 miles respectively 25 kilometers.
By car or train, the actual journey to Aalst is certainly longer, as only the direct route (as the crow flies) between Saint-Josse-ten-Noode and Aalst has been calculated here.
Air line (approximately)
25 kilometers
14 nautical miles