Visual flight rules (VFR) are a set of regulations under which a pilot operates an aircraft in weather conditions generally clear enough to allow the pilot to see where the aircraft is going. The pilot must be able to operate the aircraft with visual reference to the ground, and by visually avoiding obstructions and other aircraft.

Night visual flight rules (NVFR) defined by ICAO are the visual flight rules under which a flight may be performed at night primarily by visual reference.
For non-instrument runways, the common lights under the rules of ICAO & FAA include:

· Low Intensity Runway Edge Lights(White/White, White/Yellow or Yellow/White) are installed along the edges of the runway.
· Runway Threshold/End Lights are installed at either end of a runway consisting of at least six lights equally spaced not more than three meters from the runway extremity. Bi-directional red/green lights must be used if the airport is used in both directions.
· A Simple Approach Lighting System should be provided to serve a non-instrument runway where the code number is 3 or 4, except when the runway is used only in conditions of good visibility or sufficient guidance is provided by other visual aids.
· Taxiway Lights(Blue) are installed along the edges of each taxiway. They define the lateral limits of the taxiway.

A typical case is the Brazil FREIJO Airport completed by DoubleWise in 2020. Other airstrips are similar to FREIJO Airport in the installation of solar visual lighting system.