One major use that the military has for these small aerial vehicles is for search and rescue operations. It is no secret that disasters can happen anyplace at any time. That is why it is important to have options available that you can use in an emergency situation. A small UAV or UAVs are used in this scenario.
Another option is to use them for firefighting. Water sprinklers can only do so much in a pinch. In some cases water supply lines get cut and that is when a UAV would be able to save the day. Since they can stay aloft for hours on end this is a huge benefit to them.
The military also uses UAVs for surveillance. They can watch from above to monitor troop movements and even for traffic violations. This gives them an eye on any activities on the ground that they may not be aware of. This is very helpful to the military as it helps them plan for future conflicts.