A hovercraft (short: hover) is a craft capable of traveling over surfaces while supported by a cushion of slow moving, high-pressure air. Hovercrafts are very fast, mobile vehicles, being only units capable of traveling on the surface of water, instead of submerging.
A tank is a tracked or wheeled armoured fighting vehicle designed for front-line combat. It has limited mobility across terrain comparing to Mechs but may achieve higher speed under same tonnage. For the sake of simplicity the wheeled vehicles are also considered as Tanks.