Both are FAA traffic management initiatives used when more flights are headed to an airport than it can safely accept. The difference is how hard they hit the brakes.
| Ground stop | Ground delay program | |
|---|---|---|
| What happens | Departures to the airport stop completely (from the included airports) | Flights still depart, each at an assigned later time |
| Your delay | Open-ended until the stop is lifted or extended | A specific delay, set by your flight's EDCT |
| Typical length | Usually short: often under an hour or two | Often several hours, sometimes most of the day |
| When it's used | Sudden problems: storms, outages, emergencies | Predictable shortfalls: forecast fog, wind, all-day volume |
| What you'll see | Flight shows delayed with no firm time | Flight shows a new, specific departure time |
Ground stop
A ground stop holds every flight bound for the affected airport at the included departure airports. It's blunt but fast, which is why it's used when conditions change suddenly. It has a scheduled end time that may be extended.
Ground delay program (GDP)
In a ground delay program, the FAA sets an arrival rate the airport can handle and gives each inbound flight an Expect Departure Clearance Time (EDCT) (what an EDCT means). Flights wait at their origin rather than circling in the air, which saves fuel and keeps things orderly. The FAA publishes the program's average and maximum delay, which you can see on GroundStop.app's live map and airport pages.
Other programs you might hear about
- Airspace flow program (AFP): like a GDP, but for flights through a congested piece of airspace rather than to one airport.
- Miles-in-trail: controllers space out aircraft along a route, which can cause smaller departure delays.
- Arrival and departure delays: general delays reported by an airport without a formal program.