FlightSide is live

Alex here.

This is the first post on the FlightSide journal. I'll use it to share updates, experiments, and small aviation things I notice while building the project.

The first version of FlightSide is now live.

FlightSide answers a simple question I kept running into when booking flights: which side of the plane gets the sunlight? If you like window views this can matter quite a bit. Sometimes you want the light for photos or scenery. Sometimes you prefer shade, like I do.

There used to be a small tool that showed the sun along a flight route and helped you figure this out. It was simple and surprisingly useful. Over time it stopped being maintained and eventually stopped working. I kept thinking someone would rebuild it. Eventually I realized nobody had, so I started building my own version.

What FlightSide does

You pick two airports, set a departure date and time, and enter the approximate flight duration. FlightSide then shows your route on a map together with the sun's position, the moving day/night line, and a recommendation for which side of the plane is more likely to get sunlight.

Follow the flight

One thing I wanted was the ability to see how the light changes during the flight. There's a time slider that lets you move through the trip from takeoff to landing. As you drag it, the aircraft position moves along the route and the sun and day/night line shift across the map.

Times are shown in each airport's local timezone so they match what you actually see on your ticket.

A simple example

Imagine a late afternoon flight from San Diego to Seattle. You might take off with the sun on one side of the aircraft. As the flight continues north the angle of the sun shifts, and depending on the season the day and night boundary can approach the route as well.

By the time you are nearing the Pacific Northwest, the light can be coming from a very different direction than it was at departure. FlightSide lets you see that progression before the flight even happens.

A couple quick notes

Overnight flights
Yes, it works the same way. You can see when the route passes through darkness and when dawn or dusk crosses the flight path.

Clouds
FlightSide shows where the sun is relative to the aircraft. During daylight, the side facing the sun is usually the brighter side of the cabin, though clouds can soften the light.

One small aviation detail I've always liked: on westbound evening flights you can sometimes watch the sunset for a surprisingly long time because the plane is flying with the moving day and night boundary. It can feel like the sun just hangs outside the window.

That's the first version of FlightSide. You can pick a route, watch the sun move along the flight, and decide which side of the plane to book before you ever get to the airport.

More updates soon.