The calculated distance (air line) between Khān Shaykhūn and Manbij is approximately 105 miles respectively 168 kilometers.
By car or train, the actual journey to Manbij is certainly longer, as only the direct route (as the crow flies) between Khān Shaykhūn and Manbij has been calculated here.
Air line (approximately)
168 kilometers
91 nautical miles