What happens when you flicker a creature that has an aura attached to it?

When a creature is 'flickered' (exiled and returned to the battlefield, typically by a spell or ability), it leaves the battlefield and returns as a brand-new object. Under CR 400.7, a permanent that moves zones loses all memory of its previous existence — it is treated as an entirely different object.

An Aura enchanting a creature requires a legal enchantment target to remain attached. When the creature leaves the battlefield, the Aura loses its target. Under CR 704.5n (state-based actions), if an Aura is on the battlefield but not attached to anything, it is immediately put into its owner's graveyard. This happens as a state-based action the moment the game checks after the creature has been exiled.

When the creature returns to the battlefield, it is a new object. There is no mechanism that causes the Aura to automatically reattach — it is already in the graveyard. If the flickering effect said 'return it to the battlefield with the Auras attached,' that would be a special exception, but standard flicker effects (like Ephemerate or Conjurer's Closet) do not do this.

Concrete example: You control a Grizzly Bears enchanted with Eldrazi Conscription. An opponent plays Restoration Angel, flickering your Grizzly Bears. Grizzly Bears is exiled, Eldrazi Conscription loses its object and is put into the graveyard as a state-based action. Grizzly Bears returns to the battlefield as a vanilla 2/2 bear — no Aura, no trample, no annihilator.

Note: If you control the flicker and the Aura is yours, the Aura still goes to the graveyard — there is no way to 'save' it through a standard flicker unless a card specifically provides for it.