Tutorial on Air Defence Thread - Red Alert 2 YR: New Horizons mod for C&C: Yuri's Revenge

For true anti-aircraft deterrence a multi-layered defence is required (much as is the way in real life). To achieve this, each faction has a variety of countermeasures at their disposal, much of which is based on their real-life counterparts. So lets go into detail of what they have to offer;

Allies

AA-Capable Units: Guardian G.I., prism Trooper, jetpack trooper, patriot system (mounted on I.F.V., as well as stationary emplacement), close-range laser defence, various missile-based weapons on various vehicles (including land, sea, and air; such as Aegis cruisers, Apache attack helicopters, other aircraft), machineguns/autocannons (such as mounted on helicopters).

Soviets

AA-Capable Units: Flak trooper, flak track, lunar trooper (jetpack), missile trooper, flak cannon, S-250, S-300, pantsir S-1, various missile-based weapons on various vehicles (including land, sea, and air; such as Missile corvettes, the Kirov-class battlecruiser, Mi-28 attack helicopters, other aircraft), machineguns/autocannons (such as mounted on helicopters).

Yuri

AA-Capable Units: Rocket trooper, jetpack trooper, flak cannon, gattling gun system (mounted on gattling tank, as well as stationary emplacement), various missile-based and laser-based weapons on various vehicles (including land, sea, and air; such as cobra attack helicopters, ships, aircraft, garrisoned vehicles).

However, it's not so much the individual units that are important; the tactics used are perhaps even more important. Studying the behaviour of the AI can also show some useful tactics. For example, columns of military equipment tend to be escorted by AA-defence-capable units, some of which are AA-exclusive specialists (such as the S-250, S-300's). Escort your mobile forces with IFV's, pantsir S-1's, gatttling tanks, and even Helicopters. As for base defence, set up the stationary defence emplacements in tandem with mobile defence units (this can be helpful if say, the attacking air group bypass the stationary defence points). Other factors can help as well; radar buildings (and units) can offer an early warning of an incoming attack, and inversely radar jammers can disrupt an air assault.