What defines the cruise phase of flight?

The cruise phase of flight is characterized by the aircraft operating at a stable and constant altitude. During this phase, the aircraft maintains a steady airspeed, and the pilots make only minor adjustments to altitude and heading as necessary. This allows for efficient flight over long distances, with optimal fuel consumption and minimal pilot workload.

While other phases of flight, such as takeoff or landing, involve more dynamic changes in altitude and speed, the cruise phase is defined by its stability. The focus is on sustaining flight in a predictable manner, which contrasts with scenarios involving maximum speeds, landing approaches, or takeoff accelerations. This stability is essential for long-haul operations, where pilots can manage other tasks or prepare for the next segment of the flight.