Bring plenty of rockets, armor, weapons, and food.
You do not need to beat the Ender Dragon to get an elytra, but it makes navigation safer. sky's the limit 2048x
Bring many Ender Pearls for navigating gaps between islands. Phase 2: Reaching the Outer Islands Bring plenty of rockets, armor, weapons, and food
Open the chests on the ship for enchanted diamond gear and extra Elytra. Bring plenty of rockets
This guide focuses on the "Sky's the Limit" advancement in Minecraft, which requires obtaining Elytra. Based on the 1.21+ updates, Phase 1: Preparation (Pre-End)
Use this to speed up processing in modded versions like ATM9 To The Sky.