NOTE: Sticker packs do NOT appear as standard icons on your home screen. Follow these steps to use your stickers:
-Open a text thread in iMessage
-Click on the small arrow to the left of the text input field
-Click on the "A" (apps) icon
-You should see the Aviator icon. If you still don't see it, click on the Store+ icon, then the "Manage" tab, and there you can toggle the switch for Aviator to the on setting.