Set waypoints without specifying an altitude


I want to drop a glider from a relatively high altitude and let it glide through waypoints. Since it will only glide, no propeller is going to be on the glider. I only want the glider to glide over a specific area by following a set of waypoints for the lat and long coordinates but I do not care at which altitude. Is there a way to set waypoints in Mission Planner without specifying the altitude?

Thank you