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