How carrier anti-submarine patrol aircraft worked

How were anti-submarine patrol aircraft used to defend carriers, and who directed them?

The carrier's plot directed patrols ahead of the force to search, detect, attack, or drive down slow wartime submarines.

The carrier's plot tracked the areas already searched and directed aircraft ahead of the formation, where a submarine would need to reach an ambush position. Aircraft searched visually and by radar from altitudes that made them difficult for a surfaced boat to detect. A contact might be a submarine, periscope, wake, or suspicious object, and wartime crews could attack simply to force it down or remove uncertainty. Second World War submarines spent substantial time on the surface and moved slowly underwater, so diving destroyed much of their mobility. The answer also links German access to Norway and Atlantic bases directly to the surface transit their U-boats required.