The move in which a skier leaves the ground is called an "aerial." This term refers to when a skier goes off a jump or ramp and is momentarily airborne, performing tricks or maneuvers in the air before landing.
In skiing terminology, aerials are common in freestyle skiing disciplines, where skiers perform spins, flips, or grabs while airborne.
Thus, the precise word for a skier leaving the ground is an aerial.
