The C-21 a.k.a. Dragon Assault Ship, known to the Navi as Kunsip apxa (large gunship), is a quad-rotor VTOL heavy transport and assault aircraft used by the RDA for full-scale military operations against the Na'vi, or as support during small incursions into otherwise hostile territory teeming with vicious megafauna and flora. It is the RDA's most powerful non-nuclear weapon on Pandora, coupled with heavy armor, devastating firepower and a large cargo bay for additional room for cargo or forces, making the C-21 Dragon Assault Ship a fully-functional, multi-purpose airship. The RDA only had one operational Dragon at the time of the film, though there was a second Dragon airframe on Pandora, but most of the main components hadn't arrived from Earth. Miles Quaritch coordinated the RDA's assault on the Omaticaya Hometree and the attack on the Tree of Souls from the Dragon Gunship. It was eventually destroyed by Jake Sully.
Compared to both the SA-2 Samson and AT-99 Scorpion, the C-21 Dragon is significantly larger, slower, and less maneuverable. However, with its panoply of heavy machine guns, dozens of rocket and missile pods, and possible complement of door-gunners, it can function as an excellent lead gunship when mainline Scorpions are not around or available. To prevent potentially catastrophic friendly-fire incidents resulting from careless use of such firepower, all but the door guns are constrained by friendly fire IFF (Identification Friend or Foe) avoidance codes for safety. Otherwise, it acts mainly as a military air transport and air assault vehicle, utilizing its ability to land numerous Amplified Mobility Platform suits, infantry and other military vehicles across Pandora. Its roles include acting as capital ship/flagship, assault/attack, defense and transportation/carrier. In essence, the Dragon is the military workhorse of the RDA.
The Dragon Assault Ship has the ability to deploy many infantry units and AMP suits at once and is armed with a variety of medium automatic guns, Air-to-Ground and Air-to-Air missiles, incendiary rockets, gas canister launchers, grenade launchers, plus two dual and two quad automatic gatling gun systems. All gun and missile systems are constrained by Friendly Fire Avoidance Codes (IFF Lockout). The Air-To-Ground missiles and rocket pods are mounted on three huge stub pylons at each side, which are all in a symmetrical set.
Rather than aiming manually, a human gunner indicate targets and delegate tasks to the multiple gun and missile systems, which then execute orders accordingly.
Before Pandora was first discovered, the Dragon was, and still is, being used in massed offensives against environmental terrorists and other insurgents on Earth to a predictably devastating effect. It was usually used in only the most brutal combat zones, where it leveled major enemy installations with ease before deploying its troop and vehicles onto the ground to proceed with the ground advance in earnest. This earned the Dragon's formidable reputation for being able to inflict 100% enemy casualties in any zone it was deployed to.
Later modifications were made which replaced the standard forward missile launchers with remotely manned gun-turrets around various points of the ship, allowing it to defend itself from any close-range targets. The electronics were hardened as well, to defend against constant electronic warfare attacks from terrorists.
The electronics modifications from the Terran theatre were also useful on Pandora, to protect it from fierce electromagnetic storms. This system does not appear to be perfect however, as one was downed during the conflict at the Well of Souls in 2152 by an apparent EMP wave.
Its standard propulsion system has also been modified, granting it much more forward velocity. The Dragon's original system relied solely on its four rotors for speed, which made it very maneuverable, but unsurprisingly slow. However, jet thrusters have now been added alongside its original four rotors to allow for much higher velocities while moving forward, while maintaining its impressive maneuverability.
The Dragon was evidently in use for some time prior to the events of the film, as crashed wrecks of Dragons in various states of ruin were present in Dragon's Graveyard in 2152.
Several of the craft were used in the conflict with the Tipani Clan that year. After the reservation in the Blue Lagoon was destroyed by one, three were deployed in the Battle of Vayaha Village. Commander Falco personally operated one during the race to the Well of Souls, but was outstripped by Able Ryder and his great leonopteryx.A Dragon participated in the attack on the Hometree in 2154, delivering key incendiary missiles that proved decisive in that operation. It was eventually destroyed when Jake Sully detonated two grenades on the top of the hull, and threw a missile into one of the rotors. The resulting explosion made the Dragon spin out of control and explode soon after, though Quaritch managed to escape in his personal AMP suit.
- There is an orange colored Chinese dragon painted on the right side of Quaritch's Dragon Assault Ship, directly below the right cockpit.
- With maximum payload, the Dragon is said to be able to destroy an area the size of Manhattan in six seconds. 
- The Dragon can be seen in Quaritch's i-Tag.
- There were at least seven Dragons on Pandora, as six were destroyed in the game.
- ↑ https://www.facebook.com/AvatarMovie.UK/photos/a.359703581593.145910.191638611593/10152735889931594/?type=1
- ↑ James Cameron's Avatar: An Activist Survival Guide pg 163
Pandorapedia - Dragon Gunship article