Quick read of laws, because as always its a tad more complicated Olyy example is only if they have possession of the ball when they land under 18.2.b as except for line out it always to consider if the ball has gone into touch rather than being concerned if the player has.
2.The ball is not in touch or touch-in-goal if:
a. The ball reaches the plane of touch but is caught, knocked or kicked by a player who is in the playing area.
b. A player jumps, from within or outside the playing area, and catches the ball, and then lands in the playing area, regardless of whether the ball reached the plane of touch.
c. A player jumps from the playing area and knocks (or catches and releases) the ball back into the playing area, before landing in touch or touch-in-goal, regardless of whether the ball reached the plane of touch.
d. A player, who is in touch, kicks or knocks the ball, but does not hold it, provided it has not reached the plane of touch.