There are ships in the Spelljammer campaign setting for D&D spelljammer ships use magic to fly through the void of space. A spelljammer ship has the ability to soar through the air, so would it need to be propelled by the wind?
In order for a spelljammer ship to function, it requires the aid of a magic item called a Spelljamming Helm, which resembles a chair. Once a Spelljamming Helm is attached to a ship that weighs at least a ton, it needs to be attuned to by a spellcaster. If all of these conditions are met, then the spellcaster can sit in the Spelljamming Helm and use its magic to make the ship fly through the air. The D&D spelljammer ship produces oxygen and gravity, allowing the crew to function as if they were in their home world.
The Astral Adventurer's Guide from Spelljammer: Adventures in Space features rules for 16 different spelljammer ships. These include some alien designs that were created by D&D's monstrous races, such as the mind flayer Nautiloid ship. There are also spelljammers that have sails, such as the Bombard, Flying Fish, and the Galleon. If these ships can fly and create their own magical atmosphere, then why do they need sails?
Spelljammer Ships Have Sails For Several Different Reasons
There are some spelljammer ships that start out as regular vessels, before having a Spelljamming Helm inserted into them, such as the Galleon. One of the most important things to consider when a D&D group purchases a spelljammer ship is its functionality outside of Wildspace, as some spelljammers can only land on solid ground, while others can only land on water. If the players need to visit a world with large bodies of water, then they can use the sails to travel around, which is especially important if something bad happens to the Spelljamming Helm or the spellcasters on the ship. It makes sense to keep the ship's ability to function as an aquatic vessel for this reason.
The ability to land a spelljammer on water is also important for repairs, as ships cannot be fixed unless they are properly docked unless the players have access to D&D's amazing mending cantrip. It's also important to note that many residents of the D&D multiverse are unaware of Wildspace or the existence of spelljammer ships, and players might wish to uphold a Prime Directive, in order to keep prying eyes away from their vessel and prevent stowaways. As such, it's important that a Dungeons & Dragons spelljammer blend in with other ships as much as possible, so as not to draw suspicion.
