Small Transport; Low Wing; 2 Turbojet Eng
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 10
Distraction; Situational Awareness; Workload
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Airport; Procedure; Human Factors; Chart Or Publication; Airspace Structure
I was vectoring Aircraft X into ZZZ for an ILS Approach. He was vectored through final and left high for VFR traffic on the localizer. He called the field in sight over the Final Approach Fix; was cleared for a Visual and switched to ZZZ Tower. He turned towards ZZZ1.  VFR aircraft above 1500 feet near the localizer are a conflict because 2400 feet is the crossing altitude for the Initial Approach Fix ZZZZZ. VFR aircraft departing ZZZ or ZZZ2 Class D southbound are in a head on conflict with any aircraft on the localizer into ZZZ. IFR aircraft often end up being too high for a localizer approach because they can't descend because of VFR traffic on the localizer and they get a Visual Approach instead. It's also not uncommon for aircraft to be vectored through the final approach course to avoid traffic or descend. Both of these courses of action can disorient pilots; but there is nowhere to break them out without creating another conflict somewhere else. A few miles east of the localizer is higher terrain. An aircraft at 3000 feet within 10 miles of the airport will not be able to climb to the Minimum Vectoring Altitude in time. If the aircraft continues on a vector north to parallel ZZZ1; they could conflict with a departure off of ZZZ1; likely a prop on a 020 heading climbing to 3000 feet.  ZZZ1; ZZZ; and ZZZ2 are so close to each other that it can be confusing which airport they see when they aren't able to fly a straight path inbound because of VFR conflicts.ZZZ localizer approach course need to be controlled airspace. VFR aircraft should not be able to fly on or through the localizer without talking to ATC. It's impossible to predict the actions of a VFR aircraft not on frequency. They climb; descend and maneuver around traffic they do see; sometimes making 360's.
About XA:25 PST I observed Aircraft X; who was on an ZZZ ILS Runway XXL approach; heading westbound about 2 miles east of ZZZ1.  They had gone through the ZZZ final and appeared to be flying towards ZZZ1 and not ZZZ.  I told the Local controller and the Cab Supervisor then called ZZZ1 Tower on the shout line advising them of the traffic and that ZZZ Tower was attempting to turn Aircraft to the north towards ZZZ. Aircraft X's data tag was then changed to Visual Approach; ZZZ VA XXL. Aircraft X landed ZZZ Runway XXL without incident.
A TRACON Controller and Tower Controller reported an aircraft cleared for a Visual Approach turned toward the wrong airport. Prior to the deviation the TRACON Controller had restricted this aircraft's altitude and vectored it through the Final Approach course to avoid unidentified VFR traffic highlighting the need for restrictive airspace around busy commercial airports.