Hacker News Reader

Airplane mode definitely does not disable Bluetooth - especially if you are using airpods or other Bluetooth headsets. BT radio will stay on so you can keep listening through the flight. WiFi is also able to be toggled on while airplane mode is enabled. The only thing that airplane mode does is ostensibly turn off the mobile network connectivity

Do you have any evidence that location tracking actually works when the phone is turned off (even with the Find My Phone feature enabled)?

The data is encrypted with your iCloud Keychain. Apple doesn't have access to it.