Most likely, mass hysteria over regular planes and helicopters.

But a ‘fun’ theory is it's a live exercise of using large-scale deployment of drones by the Pentagon to potentially pacify the population in case of widespread protest, insurrection or whatever else they're afraid the population might do. Perhaps as a preemptive reassurance to CEOs, billionaires and others of similar ilk that a movement based on the "Luigi Mangione" ethic can be countered even were it to happen on a wide scale.