bobfuller30004hotmail.com wrote in message
My understanding is that Ground Stops and Ground Delay Programs only
affect flights that have *not* left the departure runway yet. So, once
in the air a flight cannot be affected by the Ground Stop or Ground
Delay Program tools, but can be affected by the Slow Down or Hold
tools.

That is correct.

If I was, for example, creating a report of all
flights affected by a particular Ground Stop or Ground Delay Program,
can I simply ignore the flights that departed *before* the Ground Stop
or Ground Delay Program was issued?

Depends on the report.

D.