Ch. 597 First day of the journey, an artist starts to bloom.

Flying just above, or while touching the surface of the water would make it feel like one was on an actual sailing vessel instead of an air ship due to the waves crashing against the bottom of the hull, but it would make the Odin far less likely to be spotted while still relatively close to land or the commonly used shipping or fishing lanes. Thus it was all part of Elric and Magell's plan on how to keep the passage between Kerseye and Gagaree as unnoticed as possible.

Flying high in the air like normal would make it to where a massive air ship like the Odin that dwarfed all but the largest trading ships owned by The Empire of Kerseye and the more powerful kingdoms, visible for a rather large part of ocean below, and to anyone who was close to the shoreline.