The heroes of Kingdom Hearts 3 move between words by flying in a Gummi Ship. The flying mechanics have changed since the previous games - they are now much more complex.
Gummi Ship in Kingdom Hearts 3
Just like Sora, your Gummi Ship also gets XP - by participating in space battles. Space is rather large - there are numerous enemies, additional treasures and other attractions. KH3 features side and treasure hunting missions as well as additional fights which means that flying around the space shouldn't be boring. There is even a secret boss that can only be defeated while you are piloting a Gummi Ship.
Gummi Ship Customization
During the course of the game, you will get more Gummi Ship elements. You can equip your ship with e.g. new weapons or thrusters. Depending on the material, these blocks will also change your ship's stats. You don't have to customize your ship to beat the game. However, it is recommended if you are planning on completing Gummi Ship missions.
You can create new ships by using blueprints. You can buy them in Moogle Shop or receive by taking pictures of constellations. Another thing you can do is to create your very own design.
In space, you can encounter various enemies. By defeating them, you will get e.g. XP, HP orb, materials for customization, or unique items. Each fight has a specific difficulty level - level up your ship before you decide to attack stronger enemies. You should also customize your Gummi Ship to make it more powerful.