The Flying Gas Balloon is a giant ship with a goat figurehead, which is shaped like the horns on Caesar's head, and what seems to be decorative edgings around the sides. There are six cannons installed on the bow of the ship. In levitating the ship, each side has a duct-fan rotor with one extra propeller on top and three extra at the bottom, as well as a giant air balloon with Caesar's initials on it. Tied from the balloon to the duct-fans are two sails with the word "GAS" printed on each one.
The Flying Gas Balloon is large enough to carry the giant-sized children high in the air without difficulty.
When Caesar went to retrieve the kidnapped children from Nami and Usopp, he ordered them to return to the ship after Brownbeard attacked. After defeating the three, Caesar and the children sailed away on the ship. While on the blimp, Caesar contacted various Brokers of the underworld, with regards to his new chemical weapon.
The ship soon reached the research facility, where Caesar and the children disembarked.