Kites are a form of powered gliders, which are able to change their altitudes and maneuver in the air faster than by riding the winds alone. They can also fly faster than gliders due to their pusher props or because of their carrier vehicle. Technically they are the equivalent of today's ultralight aircraft, but as their name states, they are literally tethered to their carrier vehicle. The only exception are the Windsurfer Gliders.
This is to allow them to be reeled back down quickly, but this gives them some major weaknesses. First of all, they lack any kind of aquatic landing gear and therefore must ditch into the ocean if necessary. Secondly, they cannot fly past the range of their tether cables, which means they are limited to their carrier vehicle. This makes maneuvering awkward if they encounter obstacles on the ocean.