Definition
Published instrument flight paths used to transition aircraft between an airport and the en route structure. Departure routes (Standard Instrument Departures, or SIDs) carry aircraft from takeoff out to the en route phase, while arrival routes (Standard Terminal Arrival Routes, or STARs) bring aircraft from the en route structure inbound toward an airport for approach.
Plain English
These are the standard, charted paths that aircraft fly when leaving an airport on an instrument flight plan and when coming back in toward an airport. Departures take you out, arrivals bring you back, and both follow set routes designed by ATC.
Context Anchor
Seen in ATC weather avoidance discussions, especially when storms or other hazardous weather affect the usual paths into or out of an airport.
Why Pilots Care
Using the correct routes during departure and arrival keeps the aircraft safely separated from weather and other traffic in the busiest phases of flight.
Intuition Check
Do not read this as just any path a pilot happens to choose. In this context, departure and arrival routes are the recognized or assigned paths used to manage aircraft moving into and out of an airport area.
Example Sentence 1
ATC offered a deviation along the arrival route to keep us clear of a line of thunderstorms ahead.
Example Sentence 2
The arrival route was adjusted to avoid the convective cells reported near the airport.