I don't think flying is really dangerous for most people who have tinnitus/hyperacusis, because most of them are very sensitive to high frequencies, and the frequencies of the plane engines are low. Personally, I am more disturbed when the crew makes an announcement, which is sometimes very high in volume.I can definitely recommend bringing/wearing earplugs. I hadn't flown since getting my tinnitus until this April, and I was honestly surprised how loud/irritating the noise on the flight was before I put my plugs in (I do have hyperacusis too, though not as bad as a lot of folks). It was just a short one-hour flight, so not a big deal in the end. But it would have been really difficult without the ear plugs.
Anyway, I strongly advice to carry earplugs when you travel... (I always carry them).