A Wing is a unit of military formation generally used for aerospace and aviation units. It is generally made up of multiple Squadrons. The Clans, ComStar, and the Word of Blake do not use the term in their military organization.
Usage By Faction
A Wing is made up of three Flights of twelve fighters, plus a Command Triple, for a total of thirty-nine fighters. Reinforced wings also exist, which have an extra Flight, for a total of fifty-one fighters. Above the Wing in Capellan Aerospace Organization is the Fleet Regiment.
A Wing consists of three Companies, for a total of thirty-six fighters. Each Company is broken down into two Flights of six fighters, the equivalent of standard Squadrons, which are further broken down to three Lances of two fighters. Three Wings makes a Regiment, however fielding a full air regiment is a rare occurrence; most Wings will be individually assigned to a BattleMech regiment to provide air support.
A Wing consists of three Squadrons plus a Command Flight, for a total of twenty fighters. Above the Wing is the Aero Regiment, or, in an RCT, the Aerospace Brigade. Two types of Wings existed in the AFFS, the Regimental Wing and Independent Wing. Regimental Wings were assigned to BattleMech regiments, charged with protecting the regiment's DropShips during interstellar travel and providing close air support and combat air patrols in battle. Engineers were provided to set up a base for the Wing, complete with poly-turf runway, hangers, and air defenses maintained by conventional craft and missile batteries. The Independent Wing was of the same composition as a Regimental Wing, but instead of being assigned to a specific regiment were free to pursue their own missions.
The FRR follows DCMS organization for their aerospace forces. A Wing consists of three Companies, for a total of thirty-six fighters. Above the Wing is the Regiment.
A Wing is made up of three Squadrons, for a total of eighteen fighters. Reinforced wings also exist, which have an additional Squadron, for a total of twenty-four fighters. Above the Wing is the Regiment.
An Air Wing consists of three Squadrons, for a total of eighteen fighters. Reinforced wings also exist, which have an additional Squadron, for a total of twenty-four fighters. Above the Wing is the Regiment, or, in an RCT, the Aerospace Brigade. Air Wings, while normally assigned to BattleMech regiments, also had additional duties of protecting DropShips during planetary assaults, escorting friendly JumpShip convoys, and working in conjunction with garrison forces on friendly planets.
There are a wide range of schemes used, but generally, a Mercenary Wing consists of three Squadrons, each Squadron composed of three Air Lances, and a Command Lance, for a total of twenty fighters. Two Wings and Command Lance form a Regiment.
A Taurian Defense Force wings typically consist of two flights, with each flight consisting of two lances of two fighters, for a total of 8 fighters. TDF wings have, over the centuries, begun to trend towards using heavier and more protective designs, as good Taurian aerospace fighter pilots tend to be as rare as they are skilled.
The Alliance's five aerospace fighter wings are closer in structure to the aero regiments of other states, each consisting of three regiments of three squadrons, plus a command squadron. This puts each wing at a whopping 60 fighters. 
In the SLDF a Wing was made up of a larger number of aircraft, making it more akin to the aero regiment of the thirty-first century, and included its own transportation, support and combat support attachments. Wings were categorized one of four ways:
- Ground Aero Wing
These wings were made up of 54 aerospace fighters divided into nine squadrons, each squadron consisting of a single model, and attached to divisions to provide air superiority and ground attack functions. In many cases these wings also included a full regiments of conventional aircraft (primarily geared towards close air support with secondary mission of providing reconnaissance) and transport aircraft, each also organized into nine squadrons of six craft.
- Fleet Aero Wing
Fleet wings had no set structure but consisted of all of the fighters comprising the vessels of a naval squadron along with any other fighters and support craft assigned to it for a given operation. Their mission was the protection of the squadron's WarShips, DropShips and JumpShips, with the secondary task of achieving air superiority over a battlefield during the initial stages of a planetary assault until such time as a GAW or other fighter support took over.
- Independent Aero Wing
An Independent Aero Wing was capable of fulfilling the duties of another aero wing or supplementing them in combat. Their composition was similar to a GAW, with additional intelligence gathering and electronic warfare capabilities and a battalion or more of paratroopers.
- Attached Aerospace
A term referring to the aerospace fighters directly integrated into independent regiments, much like the modern regiment they consisted of three squadrons of fighters, with a pair of fighters assigned to each company. They also did not consist of same support units as found in other wings and so were more reliant on other units or local facilities.
- Field Manual: Capellan Confederation, pp. 22-23, "Aerospace And Naval Assets"
- Field Manual: Draconis Combine, pp. 15-16, "Aerospace Assets"
- Field Manual: Federated Suns, pp. 23-24, "Aerospace Units"
- Field Manual: ComStar, pp. 64-65, "Unit Structure"
- Field Manual: Free Worlds League, pp. 18-19, "Aerospace And Naval Assets"
- Field Manual: Lyran Alliance, pp. 24-25, "Aerospace And Naval Units"
- Field Manual: Mercenaries, p. 31
- Field Manual: Periphery, p. 52, "Aerospace Assets"
- Field Manual: Periphery, p. 87-88, "Alliance Aerospace Arm"
- The Star League, p. 134
- Historical: Liberation of Terra Volume 1, p. 34-35