Drone

A Drone is a flying technology on Earth.

Season Two
In Bodyguard of Lies, Murphy, Jaha, Craig, and Richards discover a massive solar panel field in the Dead Zone and comes across a drone, which begin taking off across the shore of a sea. The group decides to follow it. In Blood Must Have Blood (Part 2), after leaving Murphy behind at the lighthouse, Jaha decides to follow it. Later, while chasing after a drone, Jaha encounters a group of drones surrounding a well kept mansion.

Season Three
In Wanheda (Part 1), after being trapped in a bunker at the lighthouse for 86 days, Murphy manages to escape, before encountering a drone. After chasing a drone, Murphy sees many drones flying around a well kept mansion. In Wanheda (Part 2), Emori mentions about the drone to Murphy.

In Nevermore, a drone spots Bellamy and Monty outside, before Bellamy shot down the drone.

In Red Sky at Morning, Bellamy realizes that the drone managed to follow them to Luna's place and A.L.I.E. manages to control some of the members of Floukru.

In Perverse Instantiation (Part 2), A.L.I.E. mentions to Clarke that her drones detected the failing nuclear power plants, 4 months ago.