Definition
A traffic management initiative used by air traffic control in which arriving aircraft are held — either airborne in holding patterns or on the ground at their departure airport — to balance the arrival rate at a destination airport with that airport's capacity to accept them. An arrival delay is assigned in minutes and is intended to spread arriving traffic out so the destination is not overloaded.
Plain English
ATC is telling you that flights into a particular airport are being slowed down on purpose, because too many arrivals are headed there at once. You may be held in the air or kept on the ground until your turn comes.
Context Anchor
You may see ADLY in FAA or ATC traffic management information, flight planning notes, or operational advisories for arrivals into a busy or affected airport.
Why Pilots Care
It directly affects fuel planning, passenger connections, and crew scheduling so pilots can adjust expectations and reserves before departure.
Intuition Check
Do not read ADLY as just being late for any casual reason. In this context, it points to a traffic-management delay affecting arriving aircraft.
Example Sentence 1
Approach advised a 20-minute arrival delay into the destination, so we requested holding at our planned fix.
Example Sentence 2
The pilot added extra fuel after learning of the expected ADLY from the ground delay program.