Airships have hulls made of balsa wood while gas bags are made from the intestines of mammoths known as goldbeater’s skin. It uses a gas known as spirit of flight* or ‘funny-air’ because of its peculiar ability to change the pitch of one’s voice. The only known source of spirit of flight is within the Freehold. Airships use wind for propulsion. When landing near the ground the lower sails are capable of being retracted into the hull.
*Authors note: spirit of flight is helium. It is harvested from geysers.