You can set a target definition for the Air Patrol order. in the example below I've set it up without adding any patrol points.
Anyone know if the air unit assigned would actually randomly hunt for a carrier unit and follow the carrier when spotted?
That would be sweet
What I have observed with air patrol is that this actually also works without a set route. The planes will randomly fly into a direction, preferably around the set home airfield until a suitable target is spotted by the patrol or allied unit, but I have only tested this on a too small map once.
The AI won’t spy into the fog and know where these specified targets are, but there seems to be some kind of cheating mechanic for Air Seek & Destroy going on if a plane has spotted a victim once:
The seeking AI planes follow this target forever even if you do some chaotic recon-moves without any allied AI units observing your recon plane. The AI plane will then endlessly follow your plane but keeps 2 hexes distance until its fuel runs out or might have a chance to attack. I’m not sure yet if the spotting range of fighters plays a role here how far the distance is. This could also happen with AI bombers chasing naval and ground units.
Whatever, I remember this well enough from nightfighters that can only attack large aircraft in the air. Whenever I took off with my strat bomber from an airfield, this AI nightfighter was immediately alerted again from far away and chased my bomber like a magnet even if no other AI unit was nearby for observation. This is truly some kind of cheating that I know of.
I need to test this more one day.