Plain English Meaning

The airplane is staying at the same height and going the same speed. Nothing is climbing, descending, speeding up, or slowing down.

Full Definition

A flight condition in which the airplane maintains a fixed altitude above a reference (typically mean sea level) and a fixed airspeed at the same time. Holding both simultaneously means the airplane's total mechanical energy — the sum of its potential energy (from altitude) and kinetic energy (from airspeed) — is not changing.

Context Anchor

Used when discussing how a pilot manages the airplane’s energy state during normal flight, especially when comparing with , , , or slowing down.