I’m pretty sure an army of drones could spot them coming and flag them for pick up in time to be caught on US territory. That’s the breach detection aspect. Then another army of helicopters could provide the response and the agents inside could apprehend and arrest them until they could be carted away for processing, detention, and deportation as necessary. If that process is carried out successfully a few hundred or thousand times, word would get back to those trying to cross and provide the deterrent.
Air intrusion detection by drone or helicopter is only one small part of the border solution.
Double fencing on each side border patrol road is a very good place to start where ever physical border barrier is appropriate.
If we look at this as a pest problem, the most effective deterrent is to eliminate the reward from illegally immigrating to the USA.
Amnesty, All health, welfare, education, and privileges afforded citizens (driver license, voting rights) Must be eliminated in order to make immigration here, unattractive.
Just like with household pests like ants - keeping a kitchen very clean (devoid of any available food) greatly reduces the incentive for entry and habitation.
Dems & Rinos dilberately want continued border crisis in order to forever lower american standard of living / culture, and to gradually facilitate North-Central-South American super state. Absolute treason.