Original: Jet aircraft generally fly much faster than propeller-powered aircraft and at higher altitudes â "as high as 10000 -. At these altitudes, jet engines achieve maximum efficiency over long distances.
Simplified: Unlike propeller-powered aircraft, jet aircraft normally fly at altitudes as high as 10,000 to 15,000 meters, about 33,000 to 49000 f/O. At these altitudes, jet engines can achieve maximum efficiency over long distances.