Fire Fighting Drones
You have a big forest fire and what would you do to control it from spreading? Well, sent in the fire brigade perhaps or sent in the firefighting airplane. But before anything is done, you will need to excess the enormity of the fire so that you know which entry point for reducing the fire. Sure you can send an aircraft or helicopter to survey but it would be much faster and cheaper to send a drone.
You can have drones that carries infra-red camera to capture the whole scene and have it instantly analyse for action. Or in a future scenario, send in big drone army that carry fire-fighting chemicals. And when the fire dies down, have the drone survey for hot spots that might rekindle the fire. All this at a much faster speed and without the risk of taking away human lives! Or you could have land drones that work like fire fighting units.