When you get to the gondola allow Elizabeth to deal with a locked entrance to the cabin. Explore the corners of the cabin to obtain some silver and a lockpick. Pull a lever found in the cabin when you're ready to continue the mission.
The upper station is occupied by several more policemen and they're guarding access to the airship. Check the area under the stairs (behind a model of the ship) to find one more lockpick and Vantage point #21 - Kinetoscope (from a practical point of view this is the same kinetoscope as the one found in the gift shop in the Hall of Heroes).
Once you've explored the station enter the elevator which will transport you to the airship. When you're on board of the airship make sure to check the entire cabin, because aside from a lot of money you'll also find Infusion #10. You may now use the console located on the ship's beak to end this chapter.