a few kinks in the flying like flying backwards and few thother cant think right now but good flying.

And I'm sitting there wondering how to fly correctly using wings.

In order to get it in game, you have to press the "load tech" button in the creative or R&D mode. You can then select the steam tab on top, which will show all the steam items you've selected. In order to get it in survival mode, you need to take a snapshot of the item in the Creative or R&D and save it to your own files.

Hope this helps!

how do I use this ingame? I'm subscribed to this but it won't appear in my game

@Entity.Giant.Soldier.png
It uses spoilers on the wings, which uses it's forward momentum to counterbalance the upwards thrust making it so it won't rocket up into the stratosphere whenever you are moving forwards.

uh, how does he keeps the same altitude?