The concept of anti-gravity technology involves the use of some form of energy field to counteract the force of gravity. The UNSC, Covenant and Forerunners have all developed some form of anti-gravity technology.
The following are examples of devices or vehicles that incorporate anti-gravity technology, used by various groups.
The UNSC possesses several iterations of anti-gravity technology, including the Antigravity plate used to manipulate gravity fields. While spinning sections are commonly used on starships to simulate gravity, humans are also known to employ "anti-gravity units" to generate artificial gravity on starships or space stations. A form of anti-gravity technology is also employed on some UNSC warships, as demonstrated by UNSC frigates that are capable of hovering and maneuvering in a planetary atmosphere without the use of extensive thruster systems. A simpler application of anti-gravity technology is Gravball, a ball game played on "repulsor courts."
Having had access to an abundance of Forerunner artifacts, the Covenant utilize anti-gravity technology to a far greater degree than humanity. Virtually all of their ground vehicles employ anti-gravity units known as boosted gravity propulsion drives to hover above the ground. Likewise, even their largest starships such as supercarriers have sufficient anti-gravity devices to make them capable of hovering in atmosphere. Various applications of anti-gravity are also commonplace on their larger structures, including High Charity where entire sections of the city were held aloft by powerful anti-gravity units. The Covenant also use anti-gravity technology in smaller scale, such as in their various forms of personal propulsion, ranging from the San'Shyuum gravity thrones to military antigravity packs. Other related technologies used by the Covenant include gravity lifts and gravity conveyors, among others.
The Forerunners had a masterful understanding of anti-gravity technology, as is evident by its many applications on Forerunner constructs. All known Forerunner automatons, ranging from regular Automated Turrets or Sentinels to massive war machines, utilize some form of anti-gravity, often referred to as buffer fields. The Forerunners also built structures only supported by powerful anti-gravity units, such as the Apex. One of the primary forms of transport on the Halo installations are the Anti-gravity gondolas, platforms that travel along predetermined paths using anti-gravity technology.