A flashing green air traffic control signal directed to an aircraft on the surface indicates what action?

A flashing green air traffic control signal directed to an aircraft on the surface indicates the instruction to taxi. This signal is used to provide guidance to pilots when they are moving on the ground, and it is specifically intended to direct an aircraft to proceed with caution while taxiing.

In the context of air traffic control, a steady green light would signify clearance to take off when in flight, while a steady red light would indicate to stop. A flashing green light on the surface does not suggest taking off immediately, preparing for landing, or ascending to cruising altitude, which are all actions that correspond to different signals and circumstances. The primary purpose of the flashing green signal is to ensure that aircraft can safely and effectively move on the ground without ambiguity regarding their actions.