On the note of “keeping your phone in airplane mode”:

No Bluetooth enabled devices is a good point too.

Those devices broadcast identifiable data whenever Bluetooth is enabled, and that data can be logged very easily. If an app has Bluetooth permissions it has the capability of logging that info. Or a simple device that logs nearby Bluetooth devices. About 2 years ago I placed a device in my apartment next to a road and within a week I had the habits of my neighbors logged with accurate timestamps. I took that device apart after that, it’s a macropad now.

So for the sake of privacy, no Bluetooth headphones, watches, etc near your “Go bag” phone when it has a battery in it. IMO avoid such devices in general.