Change your preferences here.
A hold item that increases the Base Power of all Flying-type moves by 20%. When held by a Pokemon with the Multitype ability, the holder's type will change to Flying.
Flying Arceus is immune to Spikes and Toxic Spikes—a nice thing to have nowadays in Ubers—but is hindered much more by its lack of useful resistances and weakness to Stealth Rock. Its Flying-type STAB has solid neutral coverage when backed by Focus Blast, but Ghost Arceus packs better neutral coverage while having the same resistances and no weakness to Stealth Rock, so generally Flying Arceus will find itself outclassed.
Sky Plate is also usable on Flying-types such as Staraptor that rely on Brave Bird as their main attack, as it offers a nice power boost while not having the restrictions of Choice Band or the recoil of Life Orb. However, Choice Band is still usually better for the much higher increase in power.
Abyssal Ruins, 1F.