The calculated distance (air line) between As Salamīyah and Khān Shaykhūn is approximately 37 miles respectively 60 kilometers.
By car or train, the actual journey to Khān Shaykhūn is certainly longer, as only the direct route (as the crow flies) between As Salamīyah and Khān Shaykhūn has been calculated here.
Air line (approximately)
60 kilometers
33 nautical miles