The Charge provided the momentum, the Violent Sit Kill offered the ability to stay airborne, and Wind Breath controlled the direction.
The skills of Contracted Spirits aren't as rigid as in games; they don't lock onto targets. However, if used flexibly, they can certainly develop new combat methods.
Contracted Spirits of the same strength can perform vastly differently in the hands of different Beast Masters.
The Flying Pig's flight speed was already slow, and to it, the Slime flying at full speed was like a living missile.
