Frequently asked questions

StuFly runs on watches with Wear OS 3 or later (Android) and on Apple Watch Series 6 or later, Apple Watch SE (2nd generation) and every Apple Watch Ultra, running watchOS 11 or later.

You need a phone that matches your watch: an Android phone for a Wear OS watch, or an iPhone for an Apple Watch.

StuFly needs a barometer (air pressure sensor) for accurate altitude and the variometer. Most current Wear OS watches have one, but some, especially older or budget models, don't.

StuFly works well on Samsung Galaxy Watch 4 and later. Google Pixel Watches should work but haven't been tested yet. The best way to find out whether StuFly suits your watch is to try it: every new subscription starts with a free month.

Newer watches are generally faster, more power-efficient and have brighter screens, which helps in direct sunlight. A larger screen is also easier to read in flight.

You don't need the latest model, though:

• Apple: any Apple Watch from Series 6 onwards runs StuFly well. A second-hand Series 6 costs around £50.
• Wear OS: stick to Samsung Galaxy Watches. A second-hand Galaxy Watch 6 costs around £60.

(Second-hand prices as of 2026.)

Yes. An iPhone can't pair with a Wear OS watch.

Yes. An Apple Watch can only pair with an iPhone.

The apps work the same way, but the watches differ in two ways that matter in flight:

• Barometer speed. Wear OS watches read air pressure many times a second; Apple Watches deliver about one reading a second at best. The variometer is therefore quicker and more precise on Wear OS. If the vario matters a lot to you, Wear OS is the better choice.
• Screen. On Wear OS, StuFly can keep the screen fully on for the whole flight, so you never need to touch it. Turn on Keep Screen On in Settings; it's off by default to save battery. On Apple Watch, the screen dims when you lower your wrist. On watches with Always On, the readings keep updating about once a second while dimmed, but the map only updates when you raise your wrist or tap the screen. This is how watchOS works, and apps can't override it.

Yes. With LTE (its own mobile connection), the watch can reach StuFly's online features (weather, maps and the ground elevation at take-off) without your phone.

If you always fly with your phone, it makes little difference. If you'd rather fly with just the watch, LTE keeps those features working.

StuFly's instruments (speed, altitude, heading, distance, the variometer and flight recording) work without any connection. These need the internet, through your phone, Wi-Fi or the watch's own LTE:

• Ground elevation at start-up. StuFly looks up the height of the ground where you are, for accurate altitude. Without a connection it falls back to the GPS height (see altitude accuracy).
• Moving map. Map tiles are downloaded as you fly and kept on the watch where there's space. In an area you haven't flown before, with no connection, the map background stays blank, but your track, home direction and waypoints still show.
• Weather. The wind and cloud screens need a connection and stay empty without one.
• Subscription check. StuFly checks your subscription online from time to time and keeps working offline for at least 7 days after its last successful check. If you'll be somewhere without signal for longer, open StuFly once with a connection before you go.

StuFly is built to be efficient, but it does far more than a watch face showing the time: it runs GPS, the barometer and a bright display for the whole flight. Battery life depends on your watch model, its screen and battery size, and the battery's age and condition.

StuFly is designed to last at least 2 hours even on the oldest supported watches. Newer watches, or ones with larger batteries, can manage 5 to 10 hours.

To get the most from it:

• start every flight with the watch fully charged
• turn off Vario Screen in Settings if you don't use the variometer, which stops its extra sensor processing
• on Wear OS, leave Keep Screen On off (the default) unless you need the display on all the time
• expect less in cold weather, as with any battery

GPS on its own is poor at altitude. StuFly combines it with the barometer, which measures height changes very precisely.

When you start StuFly, it looks up the real ground elevation where you're standing and uses that as its reference. In flight, the barometer tracks your height from there. This assumes the ground-level air pressure doesn't change much during a typical 1 to 2 hour flight. Together this gives accurate altitude almost all the time.

If the altitude looks wrong, the usual causes are:

• StuFly couldn't look up the ground elevation when it started (no connection), so it used the less accurate GPS height. You can also choose this deliberately with Start with GPS Elevation in Settings.
• The air pressure changed a lot during the flight, for example when a weather front came through.
• StuFly is showing a different altitude type from the one you expect. QFE is your height above the take-off point; QNH is your height above sea level. Switch with QNH Altitude in Settings; the icon on the flight screen shows which one you're seeing.

On Wear OS, very accurate: it's sensitive enough to register you raising and lowering your wrist, and it's well suited to general free-flight use. On Apple Watch it's slower to respond, because of the barometer differences described in Wear OS vs Apple.

If the readings are jumpy, the watch's pressure sensor may be sitting in the airflow. Try covering it with your sleeve.

No. Your flights stay on your watch and, once synced, on your phone. They are never uploaded to a server. They leave your phone only if you choose to share them, for example by email or WhatsApp, or save a backup somewhere.

To show weather, maps and place names, StuFly sends your current location to those services, without your name or any account details. The privacy policy has the details.

The watch app stops working until you subscribe again. Everything in the phone app stays available: your flights, tracks and waypoints are never deleted.

Yes, including between Android and iPhone:

1. On your old phone, open StuFly's Backup & Restore and create a backup.
2. Put the backup file somewhere your new phone can reach, for example by emailing it to yourself or saving it to cloud storage.
3. Install StuFly on the new phone, open Backup & Restore and restore the file.

All your flights and waypoints will appear on the new phone.

No, unfortunately. Google Play and the App Store are completely separate, so a subscription can't move between them. Cancel the old subscription in the store you bought it from, then subscribe again in the new one. Your flights and waypoints can still come with you (see moving to a new phone).

Absolutely. In the phone app, tap Report a problem on the home screen. If it's about a particular flight, use Report a problem with this flight from that flight instead.

Describe what happened, pick the flight if it's about one, and add your email address. Then tap Send report. StuFly sends your description with the app's logs, plus the flight's track and watch log if you picked one, and shows you a reference number. We'll reply by email.

The more you tell us, the quicker we can fix it:

• what you were doing, what happened, and what you expected to happen
• whether it happened once or keeps happening, and if you can make it happen again, how

No internet just then? Choose Email instead to send the same report from your email app, or write to contact@stufly.app.

Please send it to contact@stufly.app. StuFly is improving all the time, and I'm always keen to hear how pilots use it and what would make it better.

Thank you! A review on Google Play or the App Store is the best way to help new pilots find StuFly. You can also point friends to stufly.app or tell them to search for StuFly in their app store. Every new subscriber gets the first month free, so there's nothing to lose by trying it.