Low-altitude aerial drones, operating in disaster zones, equipped with sensor suites capable of detecting people in need of aid, as well as packages of said aid (life jackets, first aid, etc.) to deliver, can serve as a first-response to disasters, potentially saving lives before rescue teams are even able to access affected areas.
Airborne drones (both high and low endurance) can assist search and rescue teams working in disaster zones by locating people in need of rescue. A fleet of small drones could cover many times as much ground as a single search helicopter at a fraction of the cost, allowing actual rescue teams to act more efficiently (given that the drones have already located survivors throughout the affected area).
In the event that a hiker becomes lost in one of the world’s many expansive natural reserves (like American national parks), aerial drones could assist search teams in locating them using infrared camera suites, and either guiding the hiker to safety or guiding search teams to the hiker.
Providing an aerial view with which to gather data on fires for first responders
Heavy-lift aerial drones offer a solution to blazes that occur in high-rise buildings by carrying hoses up to the affected floors much more quickly than a crew of firefighters taking the stairs, without risking the lives of said firefighters.
Whether it be a man-made or natural disaster, drones (ground, underwater, and air alike) are valuable tools for collecting data on the conditions of the affected environment. The versatile suites of software drones can carry allows them to gather a wide variety of information on the effects the disaster is having on the environment (including wildlife, plant health, water toxicity, etc.) in real time.
Airborne drones (likely larger, higher range and altitude vehicles) have the potential to provide emergency internet access to area affected by natural disasters, providing aid workers with a vital connection to both each other, and potential victims trapped within areas otherwise cut off from the rest of the world.
Harnessing the potential for cheap, efficient delivery that small airborne drones offer, emergency aid supplies meant to help fight diseases like malaria in impoverished regions could be distributed via a fleet of nimble delivery drones, cutting down on the response time to outbreaks of potentially contagious diseases in areas that lack the infrastructure to deal with them otherwise.