It may have escaped you, but all night flying aircraft are equipped with navigation lights. Green, red or white, these lights are essential in flight, as explained by Mathieu Ranque, flight instructor: "All aircraft have the same navigation light coding, i.e. a red light at the tip of the left (port) wing and a green light at the tip of the right (starboard). There is also a white navigation light as far aft (rear) as possible on the tail or behind each wing tip. The reason for these navigation lights being the ability to identify the direction of an aircraft, whether it is heading left, right, moving away, or coming toward us."
With each wingtip light being visible from ahead of the ‘plane and covering an angle of 110° toward the left or right, together with the aft light and its 140° sweep, the aircraft is visible through 360°. If an aircraft is flying in our direction we will see its two forward facing wingtip lights, if flying to the left or right, one wingtip and the aft light, and if moving away, only the aft light. All this is a maritime legacy. For night-time visibility and to avoid any collision between two boats or ships, they have a red light to port (left), green to starboard (right), and a white stern light.
Aircraft are also equipped with other lights (flashing, rotating anti-collision strobe lights, and tail logo lights), plus landing, wing, and taxiing lights; although the latter are not used to indicate the movement of an airplane in flight. Their functions, like any other, are to increase the ‘planes visibility, such as to facilitate ground inspection by the mechanics of certain parts of the aircraft (landing gear, wings, etc.), or illuminate taxiways when the ‘plane is taxiing.