Definition
A level maintained during a significant portion of a flight. It is the altitude or flight level at which an aircraft flies the en route segment between climb and descent.
Plain English
The altitude you settle at and hold steady once you've finished climbing, and stay at until it's time to come down.
Context Anchor
Used in flight planning, ATC clearances, and en route altitude discussions.
Derivation
“Cruising” comes from the idea of traveling steadily rather than maneuvering or stopping. “Level” here means a vertical position in the air, not whether the airplane’s nose is perfectly level.
Why Pilots Care
Proper selection of cruising level ensures vertical separation from opposing traffic and optimizes fuel efficiency and performance.
Intuition Check
Do not read “level” here as “flying perfectly flat.” In this term, “level” means the height the aircraft maintains during the cruise portion of the flight.
Example Sentence 1
After reaching our cruising level of 8,000 feet, I leveled off and set cruise power.
Example Sentence 2
According to the cruising level table, eastbound aircraft fly at odd flight levels.