I thought it’s going to link to Tesseract

Your answer to “how to harden SSH?” is “harden SSH”?

I know your two other points gave concrete suggestions, but it’s pretty funny you suggested to “harden sshd” when that is what OP is asking how to do.

Yes, what’s your point? Airplane mode turns off the cellular, Wi-Fi, and Bluetooth. You can then turn Wi-Fi and Bluetooth back on if you choose to, which only leaves the cellular network disabled.

I don’t know your threat model, but if airplane mode is not enough, then I wouldn’t trust wrapping it in tinfoil either, as that would be less reliable. There are of course better ways than both of these methods. Like leaving your phone home.

I’ve never had a phone that keeps Bluetooth or Wi-Fi on when enabling airplane mode, but sure, if yours does that then of course also disable them separately.

Airplane mode is supposed to stop any radio transmission from your device. GPS does not transmit anything, so there is no reason to disable it.

So does, you know, airplane mode