Understanding these speeds can provide a fascinating insight into the realm of aviation. On average, commercial planes cruise at about 575-600 mph (925-965 km/h, 500 to 521 knots, 0.78 to 0.81 Mach). Private jets typically cruise at around 500-600 mph (805-965 km/h, 435 to 521 knots, 0.68 to 0.81 Mach).