What is an effective way to signal to an aircraft to stop?

Holding up a red flag or batons is an effective method for signaling an aircraft to stop because these tools are specifically designed for safety and communication on the ramp. The color red universally indicates a stop or danger, making it instantly recognizable to pilots and ground crew. Using a flag or baton also provides a clear visual signal that can be seen from a distance, ensuring that the aircraft operator understands the instruction without confusion.

The other options may not convey the urgency or clarity needed in high-traffic ramp situations. For example, waving arms quickly could be misinterpreted or go unnoticed in noisy environments. A flashlight might be useful in low-light conditions, but it could lack visibility during daylight. Shouting may not be effective given the noise levels on the ramp and can lead to miscommunication. Consequently, the use of a red flag or batons provides a standardized and clear method for ensuring safety and effective communication with aircraft.