Is highlighting of an aircraft required?

Highlighting of an aircraft is not a required procedure according to typical standard operating procedures. This means that there is no mandate to highlight the aircraft in all circumstances, regardless of flight type or operational details. The focus is instead on proper documentation and communication practices that ensure safety and clarity within the sky and on the ground, rather than on visual cues like highlighting.

Additionally, the implications of the other options suggest specific conditions under which highlighting might be necessary or optional. However, in the standard procedures outlined, highlighting is not a requirement for any category of flights, including international or those with special instructions. This understanding is pivotal for maintaining effective operational protocols without unnecessary procedural complexities.