Airline and commercial pilots fly and navigate airplanes or helicopters. Airline pilots fly for airlines that transport people and cargo on a fixed schedule. Commercial pilots fly aircraft for other reasons, such as charter flights, rescue operations, firefighting, aerial photography, and crop dusting. Many pilots learn to fly in the military, but a growing number now earn an associate’s or bachelor’s degree from a civilian flying school. All pilots who are paid to transport passengers or cargo must have a commercial pilot's license and an instrument rating. To qualify for a commercial pilot’s license, applicants must be at least 18 years old and have at least 250 hours of flight experience.