Answer: Drones string power lines in a multi-step process. A specialized industrial drone, equipped with a reel, carries a lightweight but highly resistant pilot line from one pylon to the next. The drone carefully lays this line across the tower and brings it down to the ground team. This pilot line is then used to pull a heavier guide wire, which ultimately pulls the final, heavy-duty power cable into place. This method eliminates the need for manual handling of the initial lead line, ensuring a smoother and more controlled installation.