Here is the full list of all 12 Merchant of the Skies achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Fed the Fish God
Completed the Money Accumulation goal
Found the Giant Island
Bought an island
Put money into bank
Bought a new ship
Fueled a ship
Completed first quest
Supplied inns with bread and apple juice
Built a lighthouse
Restored botanical garden