The calculated distance (air line) between Khān Shaykhūn and Aleppo is approximately 60 miles respectively 96 kilometers.
By car or train, the actual journey to Aleppo is certainly longer, as only the direct route (as the crow flies) between Khān Shaykhūn and Aleppo has been calculated here.
Air line (approximately)
96 kilometers
52 nautical miles