From ValheruG:
I noticed an odd Flying ring behaviour (haven't tried other rings) upon entering Twilight forest. I entered via portal and the ring was in my inventory - the flight option wouldn't work until I moved the ring to hotbar. I then tried the reverse placement. It also didn't function until dragged it from hotbar to inventory. In both scenarios I placed the ring back to its original place after I was airborne for a while and it continued to work fine. Just thought I'd mention it.

Wrong repo :P