I got a question about using airplane mode on the Apple Watch. As you probably know, airplane mode turns off all wireless communication on your device. You can do this on the iPhone, and on the Apple Watch. And, if you want the two devices to mirror each other, go to the Watch app on your iPhone, choose General > Airplane Mode > Mirror iPhone.
If you do this, then activating airplane mode on either device will also activate it on the other device.
To activate airplane mode, go into Control Center on your Apple Watch and tap the little airplane button.
So the question I had was about why when you deactivate airplane mode on one device the other device doesn’t also deactivate. While it’s not that obvious, the two devices can’t communicate with each other when airplane mode is active, so one device can’t tell the other to deactivate it.
In addition to Bluetooth and wifi, airplane mode turns off cellular service and GPS, so there may be cases where you only want to turn those services off, yet use Bluetooth and/or wifi. To do so, tap on their buttons in Control Center on the device where you want to use them.
I use airplane mode regularly when I go to the cinema or theater. It’s easier than turning off my phone, and it works just as well to ensure that it won’t make any noises. However, if you have notifications set to play alert sounds, they will still do so, so make sure to turn your phone to silent as well.
Slight correction: in the US at least, activating airplane mode doesn’t turn off Wi-Fi anymore; the FAA has approved it for use at all times starting a few years ago. Bluetooth and cellular transceivers, yes; Wi-Fi, no.