What does the appearance of both the red and green lights of another aircraft mean at night?

The appearance of both the red and green lights of another aircraft at night indicates that the other aircraft is approaching directly towards you. This is because the red light is on the left wing of the aircraft and the green light is on the right wing. When both lights are visible, it means the aircraft is coming head-on, since both lights are positioned to the front of the aircraft when it approaches.

In aviation, night visual clues are crucial for maintaining situational awareness, and understanding the color and position of lights aids pilots in identifying the orientation and direction of nearby aircraft. When the red and green lights are seen together, it signals that action may be necessary to avoid a collision, as both lights indicate a potential head-on scenario.

Other options in the question do not correctly describe the situation. For example, seeing these lights does not imply that the aircraft is landing, taking off, or at a distance, which would typically be indicated by other light configurations or positions.