"Robert Chambers" wrote in message
om...

Sure it is relevant, until one IFR flight has cleared the part of the
airspace relevant to his departure the second IFR flight cannot be
released for takeoff.


Yes, but at a controlled field that can occur rather quickly.



For the same reason a plane holding for IFR release cannot take off until
the IFR arrival he's waiting for has either cancelled IFR or has landed.


Not true at a controlled field.