Well, the initial Steam Workshop support is finally here! A bit clunky at the moment though, this version is mostly intended to catch internal bugs and get feedback from modders before expanding and scaling.
I will also update the modding guide to reflect the new changes within the next day.
Video Summary
I've made this 5 minute time-stamped video with a summary of how to upload to the Workshop, along with briefly going over the configs for skins and sounds.
More details
Workshop features right now
The game currently supports uploading and loading subscribed items. There is no feature to edit a mod yet, but it's coming in the next version.
The Workshop uploader builds on the local mod loader by using the same folder system. Basically, the same folders you add to mods can then be uploaded to the workshop.
Custom Skins and Sounds
Modded aircraft can now have custom skins and sounds. I missed some key parts of that for the video, I'll go in more detail when I update the guide, but basically, the skins referenced in the config only change the albedo texture for a material named MainTexture in the model.
Other
There are now additional creator name, description and fuel capacity properties for each modded aircraft.
The old Skin Select menu has been removed from the game.
Going forward
I aim to be ready with the full release of version 2 by mid September. These are the planned remaining features:
Improve the Steam Workshop integration, add edit functionality
Integrate modded aircraft into the core gameplay (e.g. be available for purchase at airfields)
New upgrade system
Landmarks
Mission system
Cross-platform Cloud Saves