Follow the light.

Manual mode samples a constant-speed great-circle route every 30 seconds. SimBrief mode follows imported timed fixes and interpolates positions between them; supplied SID/STAR fixes are retained, but missing procedure geometry is not reconstructed. The vertical profile interpolates planned altitudes and labels missing data. Aircraft altitude does not alter the light thresholds. Raw OFPs and aliases are not included in shared plans; only the route and timing needed for playback are stored locally or shared. Live imports contact SimBrief only when requested. No automatic polling occurs. Solar elevation uses NOAA’s approximate solar equations. Daylight: sun at or above −0.833° (apparent sunset/sunrise). Civil twilight: −0.833° to −6°; nautical twilight: −6° to −12°; astronomical twilight: −12° to −18°; night: below −18°. The −0.833° sunrise threshold accounts approximately for refraction and the solar disk. About the twilight stages. All categories use a sea-level horizon; cruise altitude can extend visible sunlight. Sun and Moon sky positions use SunCalc 2.1.1 at the simulated aircraft location, including approximate atmospheric refraction and lunar parallax. Map icons mark their approximate overhead points on Earth; they are not ground objects or aircraft-relative bearings. The Sun’s map marker follows the daylight model. Manual mode does not model actual routing or wind. SimBrief leg timings retain its planned speed/wind effects; Dayflight does not recalculate weather or aircraft performance. Taxi time is excluded in both modes. This is a travel visualization, not an operational navigation tool.

Each endpoint can use its location time zone (with daylight saving) or a fixed UTC offset. The departure setting converts the entered departure time and drives the origin clock. The arrival setting drives the destination clock, ETA and arrival time; it does not change the flight’s elapsed duration. Clock settings move with their locations when you swap the route. Aircraft’s local time estimates the regional time zone at the aircraft’s current coordinates using tz-lookup and the browser’s daylight-saving rules. Ocean areas may use nautical UTC-offset zones. Boundaries and coasts are approximate. This clock is independent of endpoint offset overrides. The ETA day badge compares the destination’s arrival calendar date with the origin’s departure calendar date (both local): +1 is next day, +2 is two days later, and −1 is the previous local date. Map and crossing times use UTC. The map shows smooth day/night shading at the current simulation time. The timeline and totals distinguish all three twilight stages. Speed may be entered in knots, kilometres per hour or miles per hour; switching units converts the current value. Coordinate entry accepts latitude, longitude in decimal degrees or degrees/minutes/seconds with N/S/E/W. Airport data: mwgg/Airports; map: Natural Earth (public domain). Repeated clock times during a daylight-saving change use the earlier occurrence.