Hot Air Balloon (3.5e Equipment)
From D&D Wiki
A hot air balloon represents an absolute peak in D&D technology, to be used in a campaign with some technological advances such as that, the hot air balloon lifts the person, or people off of the ground by heating up the air inside with the burner, that is semi- magical, causing the heat inside of the balloon to be considerably higher then outside, causing the buoyancy effect that make the balloon fly.
The fuel the burner uses is a magically enhanced liquid that can be bought for 150gp a bottle (which will last for about an hour of flight, as such several must be taken, and still the air balloon won't be able to go to far, but still serves many purposed in war and for transport across civilized lands by the rich.
An air balloon costs 25,000gp