I was rather surprised at this comment. A quick google later it seems that airplane mode turns off all radio communication (as I suspected), but apparently it is possible to turn Bluetooth or WiFi on while remaining in airplane mode. At least for some phones.
Airplane mode on iOS does _not_ by default turn off wifi and bluetooth, just the cellular radio. At least in Europe; it's possible that this is driven by regional regulations. Though I think pretty much everywhere allows use of the 2.4GHz and 5GHz bands in the air now.
I do this as soon as I’m home. Now both Android and iOS automatically keep bluetooth and wifi on when turning on airplane mode, provided the user does it the first time.
I do it because cell reception is quite poor at my house so calls are better off staying on wifi - also battery life is improved.
I fly regularly with an iPhone and use United’s WiFi entertainment on a regular basis. Also I often switch on airplane mode when I don’t want an international plan to activate and use WiFi all the time.
The reason being that "airplane mode" is there to save the terrestrial mobile network. It has nothing to do with the airplane, and there's no reason to turn off wifi or bluetooth on an airplane.
