Definition
The horizontal portion of a flight plan programmed into a Flight Management System (FMS), defining the route of flight as a sequence of waypoints, airways, departures, arrivals, and approaches viewed from above. It specifies where the aircraft will go across the ground but not the altitudes or speeds at which it will fly those segments.
Plain English
The side-to-side path of the flight as seen from above — the line on the map from departure to destination, made up of waypoints and route segments. It covers where you go, not how high or how fast.
Context Anchor
Seen when entering, reviewing, or changing a route in a flight management system during preflight, en route flight, or approach setup.
Derivation
‘Lateral’ comes from the Latin lateralis, meaning ‘of the side.’ In flight planning it refers to the sideways or horizontal dimension of the route — the path traced across the ground — as opposed to the vertical dimension, which deals with altitude.
Why Pilots Care
Pilots must verify the lateral path matches the cleared route to prevent navigation errors or airspace issues.
Intuition Check
Lateral does not mean the airplane is flying sideways. Here it means the horizontal, map-view route the aircraft is meant to follow over the ground.
Example Sentence 1
Before departure, the pilot loaded the lateral flight plan into the FMS, entering each waypoint from the filed IFR route.
Example Sentence 2
During cruise the crew checked the lateral flight plan on the display to confirm the next point along the route.