Airplane mode is an ever-present setting on mobile devices that is effectively an instant kill switch for all radios, those for wireless connectivity included. However, this setting can be considerably less convenient for those who depend on Bluetooth for audio. There are now signs that an Android 10 successor may allow more granular control over what it does.
https://www.notebookcheck.net/Android-11-may-be-capable-of-leaving-Bluetooth-on-in-Airplane-Mode.445975.0.html