The times you most need to check a seat are usually the least convenient. A last minute booking, a changed schedule, a layover you did not plan for. Airport WiFi can be unreliable, your phone signal is patchy, and you need to pick a seat before the good ones go.
FlightSide can now be installed from the browser and cached on the device, so it is ready when the connection is not.
Depending on the browser, look for an install prompt in the address bar or "Add to Home Screen" on mobile. It opens in its own window with the FlightSide icon. Updates still roll out normally when a connection is available.
What works offline
The main experience works fully without a connection once the app has been cached. You can pick any two airports, set a departure time and duration, and the sun position, day/night line, and seat recommendation all calculate as usual. The percentage, which side, and the time slider all run entirely in the browser with no network needed.
The map still shows the route and the sun marker. When the basemap cannot load, you will see the route over a simplified land outline instead of the full map detail, but the flight path and sun position are still there.
The journal works a bit like a social feed offline. Posts you have already opened are still there, but nothing new will load until the connection comes back.
The contact form is not available offline. It needs a connection to work, so the page says so instead of letting you write something that will not send.
When the seat decision happens later
Most seat choices happen at booking or when check-in opens, but a lot can happen between booking and boarding. Seats that were taken at booking often free up. Paid upgrades drop to no charge. Exit rows unlock.
Other times, the change is less convenient. You might get rebooked after a delay, moved to another flight after an oversold cabin, or left choosing seats for a separate second leg while you are already traveling.
Those are bad moments to depend on a fresh page load. Airport WiFi is slow, roaming data can be expensive, and in-flight internet may not work at all. Internationally, offline matters even more: once the app is on your device, FlightSide can calculate any route without using data.
That is why it helps to have FlightSide already on your phone. Open it once before you travel, and it is still available when the seat map changes, your flight changes, or you need to make a quick call from the gate.
Most of the time, the answer only takes a few seconds. The hard part is having it available at the moment you need it.
Install it before you travel. The full sun and seat calculation will be there even if the airport WiFi is not.