What does a horizontal arrow (→) in space 20 indicate?

The presence of a horizontal arrow (→) in space 20 signifies that aircraft are authorized to maintain a cruising altitude. This symbol indicates that the air traffic controller has cleared the aircraft to operate at a specified flight level without further immediate changes, allowing for steady flight and efficient management of air traffic.

In the context of air traffic operations, it represents a phase in flight where the aircraft can optimize fuel consumption and travel time while maintaining safety and separation from other aircraft. Understanding these symbols is crucial for effective communication and coordination within airspace management. This distinction is essential for controllers to ensure the smooth flow of traffic in the busy airspace system.

The other choices relate to different aspects of flight operations or maneuvers, such as redirecting traffic, preparing for landing, or entering a holding pattern, none of which align with the meaning associated with the horizontal arrow in space 20.