Definition
The airspeed at which an airplane is flown during the cruise phase of flight, typically a manufacturer-recommended setting that balances speed, fuel efficiency, and engine wear for level flight at a chosen altitude and power setting.
Plain English
The steady speed an airplane is flown at once it has finished climbing and is travelling level toward its destination.
Context Anchor
Seen when the Airplane Flying Handbook explains how to begin a climb from normal cruise flight.
Derivation
Cruise' comes from the Dutch 'kruisen,' meaning to cross or sail back and forth. In aviation it carries the same idea as in sailing: the steady, settled phase of travel between departure and arrival, after the work of climbing is done.
Why Pilots Care
Using the correct cruise airspeed delivers the fuel economy, engine temperatures, and range performance published for the aircraft; deviations increase fuel burn or reduce available endurance.
Intuition Check
Cruise airspeed does not mean the airplane’s fastest comfortable speed, and it does not mean speed over the ground. It means the airplane’s steady speed through the air during the cruise portion of flight.
Example Sentence 1
After leveling off at 6,500 feet, the pilot reduced power and let the airplane accelerate to its normal cruise airspeed.
Example Sentence 2
Selecting the economy cruise airspeed instead of the high-speed setting extended the aircraft's range by nearly 100 nautical miles.