What Is ETD? Definition & Meaning in Aviation
ETD (estimated time of departure) is the time a flight is currently expected to leave.
In plain language
It starts as the scheduled departure time and changes if boarding, loading or a late incoming aircraft causes a delay.
Example
If the aircraft for a Lahore flight arrives late from Karachi, the ETD of the next flight moves later.
Why it matters
The ETD is the earliest sign of a delay. If the estimated departure moves later while the scheduled time stays fixed, the flight is likely to leave late, even if no announcement has been made yet.