When asking the developer on Steam if it will, they said this:
Yes absolutely. We would love that. Since this is a custom engine everything takes a lot of time though, so it cannot give an estimate on when.
Really great to get such a positive answer!
It turns out, that Linux support is listed on the Steam page as well, under the "Rendering, Hardware and Platforms" heading in the Roadmap section.
It sounds like a very relaxing game. A bit weird perhaps, but it could be ideal when you're in the mood for something perhaps a bit different. The game is a sandbox, with no set rules so you basically fly around and go wherever you want. It doesn't sound like there's any set goals, which sounds strange if all you're doing is flying.
You will discover creatures, discover new lands, take on characteristics from found creatures with a possibility to find "rare mythical creatures" too.
I'm keen to give it a go, mainly to see what it's really all about.