A Hurgh Duj typically has a motor in it propelling it along. Its pilot can control how fast it's going (up to a point), where it's headed, etc. That's not the way a hot-air balloon works. So I suspect Hurgh Duj is not what you're looking for. You can probably make use of weSjech ba'Suq (which is a particular sort of balloon, I guess). Once the basket ('unwat, or maybe, in this case, 'unwat'a') is attached to the balloon, I suppose the whole thing could be a weSjech ba'Suq Duj. But I don't know if you'll need that for the story. Maybe.