Cut Halo 2 vehicles
From Halopedia, the Halo wiki
During the development of Halo 2, a number of vehicles were cut from the final game release.
The "Doozy" was a small maritime craft concepted for inclusion in Halo 2. The original idea was originally intended for Halo: Combat Evolved, though was also cut. The jet-ski-like craft was intended to have two seats, with a gunner facing backward - nicknamed by Bungie as the "nausea seat".
A vehicle of the same name is canon within the Halo universe; though it serves as a light snowmobile rather than a watercraft. Interestingly, the canon Doozy is noted to have the same "nausea seat" as described by Bungie.
The Kestrel was a small VTOL, designed to serve in gameplay as a UNSC aircraft and counterpart to the Banshee. A number of designs were concepted, though the development team had a difficult time getting the engine physics to work correctly. One of the Kestrel concepts later informed the now-canon AV-30 Kestrel; featured as a MEGA Brands Halo Toy and useable in the 2015 game Halo: Spartan Strike.
While discussing the "strike fighter" (see below), the developers at Bungie also mentioned the need for a "Black Hawk-type vehicle", which was later cut from the game. This seems to correspond with the prototype Falcon aircraft seen in very early beta builds of Halo 2, which had been prototyped in 3D shortly after the release of Halo: Combat Evolved. The vehicle in these builds is untextured and un-animated, simply appearing as a low-poly blockout model. The vehicle has a single pilot with a nose-mounted machine gun at the front of the aircraft and two side-mounted seats for passengers. The Falcon is additionally included in a rough state in map files for the Halo 2 build seen in Halo: The Master Chief Collection, and can be spawned in via modding.
Notably, a vehicle of the same name was concepted for, and cut from, the real-time strategy game Halo Wars, though in that game was to appear more akin to a UNSC jet fighter and appears to have little resemblance to the Halo 2 vehicle. The Halo 2 Falcon was intended by Marcus Lehto to be a smaller cousin to the Pelican dropship, for small-unit deployment. Following the cutting of the Halo 2 Falcon, Marcus Lehto continued to work on the idea, producing sketches between the production of Halo 2 and Halo 3 that later became Halo 3's aerial craft the Hornet. However, Lehto wasn't satisfied with the Hornet and eventually the Falcon would finally be realised in 2010's Halo: Reach as the UH-144 Falcon, a tiltrotor helicopter bearing little visual resemblance to the original Halo 2 design but filling the same "Black Hawk" gameplay role.
The Mongoose was originally intended to be a vehicle useable in Halo 2. The vehicle was fully built and animated, with gameplay of the ATV shown by Bungie in the Halo 2 Limited Collector's Edition documentary. In the build shown, the Mongoose uses the same driving sounds as the Warthog and has the aiming reticule of the Magnum. During development, the Mongoose was difficult to integrate into gameplay, with the designers trying out front-mounted guns and no weapons. Ultimately, the vehicle was cut as it interfered too much with the Warthog and Ghost.
Notably, the Mongoose was brought back almost wholly unchanged in Halo 3 and has since remained a series staple; in Halo 3 and subsequent titles, the Mongoose is a two-person vehicle with no armaments. A second player can mount the back of the vehicle and fire their handheld weapons in third-person or carry objectives (such as a flag). The idea of the Mongoose with weapons was later revisited in Halo 2: Anniversary, with the game's multiplayer introducing the Gungoose - exactly the same as the regular Mongoose but with two front-mounted and driver-fired M67 LMGs.
The strike fighter was intended as a defensive space fighter for use by the UNSC during the Battle for Earth. The vehicle would have little place in actual gameplay, and instead be a cinematic-only vehicle, similar to the Longsword seen in the final game. For gameplay, the designers needed more of a "Black Hawk-type vehicle", likely referring to the cut Falcon UNSC aircraft detailed above. Early storyboards for the levels Cairo Station and the cut level Covenant Ship show some more usage of the strike fighter; in the cut sections of Halo 2's early story, the strike fighters would have filled the role shown by the Longsword in the final game - performing an attack run on a Covenant carrier.
In later media such as Bungie.net news, the Halo Encyclopedia and the Halo Waypoint universe section, several vehicles have been described with very similar traits to these cut vehicles, namely being the (from left to right, as per the image and not including the standard Warthog) M868 Tropic Warthog, M862 Arctic Warthog and M914 Recovery Vehicle. This was later confirmed by Jeff Easterling, with the note that it can change later if 343 Industries needed.
Shadow troop carrier
The Shadow troop carrier is a troop carrier. In-game, the vehicle is only featured in the level Outskirts, driving along the Mombasa highways. These vehicles carry Ghosts in their underbelly compartments; however, a troop carrier variant exists in the files unused, and is shown in the Halo 2 Manual. This vehicle is found in the shared map content in the Halo 2 component of The Master Chief Collection, and despite being unused the troop transport variant was even retextured for the visually updated campaign of Halo 2: Anniversary.
In the Halo 2 E3 demo, the city of New Mombasa is depicted as under siege by a massive Covenant artillery cannon. During the demo, a flight of Longswords is called in to bomb the gun. While this massive artillery piece does not appear in the final game, a smaller version of it known as the Type-48 Weevil does appear in the beach section of the level Outskirts - though inactive. Through modding, the guns are found to have turning and firing animations, indicating they may have been intended to be seen firing on the city of New Mombasa in-game.