Based on typical operational limitations and design factors, the maximum speed at which a modern passenger aircraft can fly is generally restricted.
According to information found in sources discussing aircraft performance, this speed is commonly limited to Mach 0.85. This figure represents the speed of sound relative to the aircraft's speed. Translating this Mach number into more familiar units provides approximate ground speeds:
| Unit | Approximate Speed |
|---|---|
| Mach | 0.85 |
| Miles per hour (mph) | 667 mph |
| Kilometers per hour (km/h) | 1,074 km/h |
This limit of Mach 0.85, which is approximately 667 mph or 1,074 km/h, is a practical operational ceiling for most large commercial jets. It's determined by a combination of aerodynamic efficiency, fuel consumption, structural limits, and passenger comfort at high altitudes. Aircraft designed for other purposes, such as military or research, can achieve significantly higher speeds. The speed mentioned here specifically refers to the typical maximum cruising speed for modern passenger aeroplanes.
