The Forerunners created large and sizable Anti-Gravity Gondolas, that travel by utilizing anti-gravity technology to ferry individuals over long and extensive distances, that are otherwise difficult to traverse.
Types
So far, two types of Gondolas have been discovered throughout the Halos, the first near the Temple, (the Temple Gondola) and the second near the Library, (the Library Gondola). Both of these have exclusively appeared in Halo 2.
At the Temple
The smaller Temple Gondolas and underwater elevators are also the only way to reach Regret's Temple without flying. These Gondolas use anti-gravity "tethers" below and above it.
Gameplay
This Gondola is traveled upon in the level Regret, in Halo 2. It can be started by the player character Master Chief, using its switch. It cannot be stopped manually, though it automatically stops when docking to either boarding platform.
A glitch known as the Gondola Grunt exists, wherein trapping a Grunt on the second Gondola, its AI dramatically changes tactics and personalities.
At the Library
The larger Library Gondolas and the Teleportation Grid are the only way to reach the Library of a Halo.
Gameplay
This Gondola is traveled upon in the level Quarantine Zone, in Halo 2. It is started automatically by the player character Arbiter, in a cutscene. It automatically stops when docking to either docking station.