Although his swing looks a little loopy Jim Furyk is a great example of a one plane swing, he takes the club outside coming back but his delivery position is exactly on one plane.
In the one plane swing you bend more from the hips, your arms are hanging down and swinging around your chest and your finish is more rounded. It is easier to maintain because there are fewer moving parts than the two plane swing.
Change your swing and set up in order to pitch the ball on a trajectory needed for the shot at hand