Police are appealing for information after two micro light aircraft flew over the event area at Party at the Palace.
One aircraft flew low over on the Sunday night during the set of Amy Macdonald forcing the Scottish singer to stop in her tracks.
The other flew over on the Saturday.
The festival was on the weekend of August 12 and 13. Police want to identify the pilots of both aircraft at the time.
Anyone who knows who is responsible is asked to contact the local community officers on 101, or email firstname.lastname@example.org, or in confidence via crimestoppers on 0800 555 111.