The calculated distance (air line) between Letňany and Jablonec nad Nisou is approximately 50 miles respectively 80 kilometers.
By car or train, the actual journey to Jablonec nad Nisou is certainly longer, as only the direct route (as the crow flies) between Letňany and Jablonec nad Nisou has been calculated here.
Air line (approximately)
80 kilometers
43 nautical miles