When we switch on Airplane mode by googling the button in Settings app of iOS device. It turns off the WiFi and mobile data as expected. But it does not turn off the Bluetooth. This is not expected.
Default AirPlane mode turns off cellular and wifi. FAA allows bluetooth accessories, headphones, keyboards, hearing aids, etc during all phases of a commercial flight and with the AirPods, AppleWatch, Beats headphone line up Apple likely felt it was more convenient to leave BT on.
Like @Paco II mentioned though if you turn bluetooth off in AirPlane mode the next time you turn on AirPlane mode it will remember that and shut off bluetooth.
This issue here is not remembering of the state after re-enabling airplane mode.To be clear, iOS remembers your settings for Bluetooth and Wifi when enabling Airplane Mode.
This issue here is not remembering of the state after re-enabling airplane mode.
what I had pointed out is that after the airplane is enabled and all the while the airplane mode remains enabled, the WiFi gets disabled but the bluetooth remains enabled if the Bluetooth was active before enabling airplane mode.