Each plane can have up to three SP weapons - their default one, and the other two that you need to buy with MRP. The game offers a wide variety of SP weapons ranging from smart air-to-air / air-to-ground Missiles, guided/unguided bombs, rockets, additional MG pods, railguns, and even tactical lasers. These SP weapons are exclusive to their respective planes but the upgrade parts that can improve their performance can be shared or equipped to any plane in your hangar.
SP weapon selection will depend on the mission you’ll be tackling. If you’re trying to complete a mission with a lot of aerial targets, equip SP weapons that can lock-on to multiple targets from medium to long range. A lot of ground/ naval targets? Equip those air-to-ground Missiles or bombs. Guided bombs or air-to-ground missiles are perfect for surgical strikes against priority targets like tanks, SAMs and other AA emplacements. Bombs are perfect for clumped targets such as the oil tanks in the campaign Mission 08: Pipeline Destruction.
Multiplayer is a different story. Most of the time, you’ll be fighting off skilled players with superior planes equipped with their own multiplayer-exclusive parts. Shooting them down may prove to be a challenge if you’re just using a “vanilla”, setup. Since enemy players can effectively use evasive maneuvers and flares, the use of fast, hard-hitting, and precise Missiles like the QAAM or SASM will increase your Chances of hitting your target.
Railguns like the EML (Electromagnetic Launcher) and laser weapons like the TSL (Tactical Laser System) and PLSL (Pulse Laser) are very deadly in the hands of a capable pilot since there’s no warning and the damage is dealt almost instantaneously. They can be very potent in multiplayer matches though the required skill level is considerably high.