I’ve used my bluetooth headphones on all flights I’ve taken for the past few years, all of them in the EU. I don’t hide it and I never had any trouble with it.

The original Ericsson Bluetooth development boards came with a CD full of documentation that included papers describing the effects of personal electronic equipment on avionics systems. They could have just asked you instead.

Sure, always happy to help.

It’s possible to turn bluetooth on while in flight mode. People use bluetooth headphones a lot in flight. One of the premier use case of Bose’s noise cancelling bluetooth headphones is to use on planes. No announcement is made to ask people to not use bluetooth. No flight attendant asks people to not use bluetooth headphones. Planes are not crashing.

It’s probably safe to use bluetooth headphones on a plane.

Interesting to know, as mentioned I never saw them being allowed.