Basically the space flight mechanic is somewhere between Mass Effect: Andromeda and CoD: Infinite Warfare.
You use your galaxy map fast travel to go anywhere and can only fly the ship around each small “instance.”
Planetary landings are restricted to POI’s or you can land on some random spot, but the planets are broken up into chunks so you can only walk around so much before having to go back to your ship for another fast travel moment.