What is the distinction between ferry and recovery flights in the policy for slot violations?
The policy allows justification for recovery flights (carrying passengers) and ferry flights (empty) necessary to perform such a recovery flight to AMS. For ferry flights from AMS, justification is only possible if necessary for performing of the recovery flight. Justification for ferry flights from Amsterdam can only be applied if otherwise no aircraft could be hired to perform the recovery flight.
See points 27-29 of the Slot violations policy.