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