The latest version of this helpful app, called simply AltitudeAlert V3, works on all iOS devices from iPhone to iPad Pro to Apple Watch. That latter device is a nice addition if you fly with one – the app will now deliver haptic alerts in addition to pop-up notifications and audio alerts. Depending on how you set up your devices, you could have an audio alert in your Bluetooth-enabled headset, a vibration on your wrist, and a message on your iPad screen.