The Particle Swarm Optimization (PSO) is one of the most well-regarded algorithms in the literature of meta-heuristics. This algorithm mimics the navigation and foraging behaviour of birds in nature. Despite the simple mathematical model, it has been widely used in diverse fields of studies to solve optimization problems. There is a tremendous number of theoretical works on this algorithm too that has led to a large number of variants, improvements, and hybrids. This chapter covers the inspirations, mathematical equations, and the main algorithm of this technique. Its performance is tested and analyzed on a challenging real-world problem in the field of aerospace engineering.