As an audiologist, retired, I can safely say that Bluetooth sound through another device, then to your hearing aids is not going to sound great for music, no matter how expensive, and how advanced the hearing aids are, compared to over the ear headphones. You just can't get the bass through them; they are designed for voices, no matter what their marketing says. But it will work very well to hear movies and things.
Issues with other possible solutions:
You would get great sound with the over the ear ones the airlines loan you in Premium Economy or Business, but regular headphones don't plug into the sockets. The Bluetooth ones are a possibility, and the sound quality is excellent, as someone has already said. The problem you might have with this arrangement, is that, for it to be comfortable, you would have to take your hearing aids off on the airplane, which is risky. It is hard enough dealing with little things that might fall on the floor, so I would not suggest you induce more stress. Maybe you can manage without the hearing aids as you go through security etc.
As a normal hearing person, I use Bluetooth bone conduction headphones for road cycling, and sacrifice good sound for being able to hear the cars etc while I ride. I don't do this while riding through busy cities. That is another possibility for you, because you can leave your hearing aids on. It is making a complicated arrangement on your ears though, and again, I can't highly recommend it for this reason.
I find over the ear headphones the airlines provide sound good, but are not that comfortable on a long flight, due to my glasses and sleeping positions. It is indeed a difficult situation, and every choice has its disadvantages.