The Leibnitz is an airship owned by the Zeiss Central Factory built in S.1178, used for large scale maintenance and transport of other vehicles. It's the same model as other airships built by the Central Factory, but unlike them its color is orange and features work arms so it can perform its tasks. The Leibnitz makes periodic stops at Leiston Fortress to inspect its equipment and make sure it's performing properly.
When Estelle and Joshua try to find Maintenance Chief Gustav to request a combustion engine for Professor Russell's experiment with the Black Orbment, they are told he’s been at Leiston Fortress for a few days for an emergency repair on a military patrol ship, and see him returning to Zeiss on the Leibnitz. After learning that Professor Russell and the Capel unit are being kept inside Leiston Fortress, Estelle, Joshua, Tita and Agate use the Leibnitz to sneak into the fortress by stowing away in its cargo.
On the day after the group escaped from the fortress, the army visits Zeiss to check on the Leibnitz to see if it was responsible for the act. Gustav quickly moves the Leibnitz underground, to receive an overhaul and hide any traces of its involvement.
After the earthquake at Sanktheim Gate, the Leibnitz crew starts planning its leave for Leiston Fortress to load a new orbal engine onto the Arseille. By the time a different earthquake happens at the fortress, the airship is ready to undock. Aldan manages to take a picture of the Leibnitz as it leaves Zeiss to install the new engine onto the cruiser.
- Trails in the Sky FC, Chapter 3: "The Black Orbment".
- Trails in the Sky FC, Final Chapter: "Turmoil in the Royal City".
- Trails in the Sky SC, Chapter 2: "The Raging Land".
- Trails in the Sky SC, Chapter 3: "The Mad Tea Party".
- Trails in the Sky SC, Chapter 8: "Land of Chaos".
- Trails in the Sky the 3rd, Prologue: "The Gralsritter".