Hi edema,
It is my understanding that you are having some issues with Apple Music stations on your iPad Air not playing through your Bluetooth headphones. I listen to Apple Music all the time and I know it's nice to be able to listen to the radio stations through headphones. I will do my best to help you.
Since you noted that you can hear Siri through the Bluetooth speakers, can you also try out a different app like YouTube to see if you can hear the audio from there through your headphones? Also, if you haven't already, close out of the Music app and reopen it and try to play that station again. Does this happen on just that specific station, or any station you listen to?
Even though you have done some of the following steps from this article, Get help connecting a Bluetooth accessory with your iPhone, iPad, or iPod touch, there are a couple of additional ones that can help out.
- Make sure that your Bluetooth accessory and iOS device are close to each other.
- Make sure that your Bluetooth accessory is on and fully charged or connected to power. If it uses batteries, test them to see if they need to be replaced.
- Restart your Bluetooth accessory.
- Make sure that you have the latest version of iOS on your iPhone, iPad, or iPod touch.
- On your iOS device, go to Settings > Bluetooth and make sure that Bluetooth is on. If you can’t turn Bluetooth on or you see a spinning gear, restart your iPhone, iPad, or iPod touch.
- Unpair the Bluetooth accessory, put the accessory back in discovery mode, then pair and connect it again.
Thanks for stopping by the Apple Support Communities. Cheers.