When are position lights required to be displayed on all aircraft in flight?

Position lights are required to be displayed on all aircraft in flight from sunset to sunrise. This regulation is important for ensuring that aircraft can be seen by others in low-light conditions, which increases safety and reduces the risk of mid-air collisions.

By requiring position lights during this timeframe, which encompasses the hours of darkness, it ensures that aircraft remain visible to other pilots, both in the air and on the ground. This visibility is crucial, as the absence of natural light makes it more difficult to see other aircraft and navigate effectively.

The other options refer to different timeframes or circumstances under which aircraft lights might be used but do not align with the strict regulation of position lights' required use during dark hours. For instance, the one-hour specification mentioned in the second option aims to cover twilight conditions but does not encompass the clear intent of ensuring visibility from sunset outright. Similarly, the inclusion of specific time constraints, such as thirty minutes before or after sunset/sunrise, may address operational practices but are not the standard requirement for position light usage.