A helicopter is a type of aircraft that uses rotating blades, or rotors, to lift off the ground and fly. Unlike airplanes, which have fixed wings, helicopters can take off and land vertically, making them useful in various environments, including urban areas and remote locations. They are often used for medical emergencies, search and rescue operations, and military missions. The main components of a helicopter include the rotor system, tail rotor, and fuselage. The rotor system generates lift, while the tail rotor helps stabilize the aircraft and counteracts the torque produced by the main rotor. Helicopters can be powered by either piston engines or turbine engines, depending on their size and purpose.