Android 11 may support leaving Bluetooth on in Airplane Mode
Airplane mode was originally developed to avoid any risks of personal-device emissions interfering with aircraft radios while taking off or in flight. However, it has some other uses, including being right there in a pull-down menu in the event of needing a quick fix for misbehaving mobile-data or Wi-Fi settings.
However, even this level of convenience can be nullified in those who use Bluetooth for audio. This standard is not just for headphones or earbuds any more: an increasing selection of electronic aids for the hearing-impaired include the option to connect to a phone, so that the user can control this aspect of their lives while streaming content at the same time.
Therefore, situations in which airplane mode is mandatory (or, worse, switched on by mistake) would be an intensified hurdle for these users, as they may have to re-connect their aids (or perhaps even set them up all over again) afterward. It seems AOSP developers have been paying attention to issues like these, however. A recently-added commit in its Gerrit allows for finer control over Airplane Mode, in that it leaves Bluetooth on if an active Bluetooth A2DP or Hearing Aid profile is detected.
Judging by the date of its original submission (December 2, 2019), the earliest official OS in which this new potential setting could take effect is Android 11 (a major upgrade nearly guaranteed not to bear a dessert-based code-name). Hopefully, this new feature, currently known as "Context-aware Bluetooth airplane mode" will indeed arrive that soon to make the legacy quick tile this much better in the future.