Don't rule out Chaladonians... They are after all the most alchemical, growing plants and making potions...
Many alchohols coming from fruits and vegetables which need to be grown.
Stuck up has nothing to do with it, an alchemist made a very potent brew, quite possibly intended to be as a potion base, and a pilot added it to the engine one day, discovered it made the engine a lot more effective with side effects, the recipe got handed around and adjusted over time.
Regarding all the other questions from Skymonger.
Try not to let gameplay mechanics represent your immersion or roleplay point of view, instead use it as a reference, for example when I was writing my little stories for GoI, crew mates would take cover behind certain parts of the ship when under fire, leaving cover when it was safe, armour repairs would be done using abseiling pulleys and an engineer jumping down the side and rebolting the armour plates back in place, balloon repairs, grapling hook and ropes.
Crew member fell off the ship? They would splat onto the floor in the shape of a human pizza.