In addition to the galactic orbit the disk itself has it's own local gravitational pull that keeps stars in the plane by pulling up/down when a stars trajectory

In addition to the galactic orbit the disk itself has it's own local gravitational pull that keeps stars in the plane by pulling up/down when a stars trajectory takes it below/above the local disk. When we are out of the plane we loose the protective cover all the shielding the disk provides from the galactic core (electrons go zing). When in the middle of the disk there is a higher density of mater to interact with (rocks go boom). Our typical exposure to "orbits" earth & moon tends to be that they are roundish flat & smooth and we might be tempted to think the suns orbit around the galactic core is smooth, but it may be better to think of us as also bobbing up and down the highth of the disk as we go.