Hot take: Flight was a mistake and if fast traversal was an issue, the devs should have just added a super jump to help with verticality while making the glide faster.
I haven't tried it in a while, but I was pretty much able to fly all the way from Ragunna to Mt. Firmament only taking a single break on some random overworld ships near Mt. Firmament. The only thing that stopped me was the screen "blacking out or something and basically resetting where I was, artificially preventing me from reaching Mt. Firmament.