A failsafe for a covert drone? Sure, just layer it like a bad onion: start with a hard‑coded kill switch that only the operator can trigger remotely, then a self‑destruct sequence that only fires if GPS fails, add an auto‑return protocol that kicks in on signal loss, then a stealth‑mode that turns off all external emitters, and finally a last‑ditch self‑deactivation that just powers down the entire system if battery falls below a threshold. Each layer is a fallback for the previous, so you never have to choose between safety and silence.

You’re right, a lock on the kill‑switch is the linchpin. Make it a hard‑coded one‑click trigger, authenticated by a short‑lived, out‑of‑band token that can’t be spoofed. Keep the operator link alive with a heartbeat; if it drops, the drone auto‑shuts down instead of staying limping. That way, if somebody hijacks the comms, the kill switch is still the ultimate last resort. Simple, but it turns the whole system from “nice idea” into a real safety net.