A runway is a long, flat surface at an airport where aircraft take off and land. It is typically made of asphalt or concrete and is designed to support the weight of airplanes. Runways are marked with lines and numbers to help pilots navigate and ensure safe operations. Runways vary in length and width depending on the type of aircraft they accommodate. For example, larger planes like the Boeing 747 require longer runways than smaller aircraft like the Cessna 172. Proper maintenance of runways is crucial for aviation safety, as any damage can affect landing and takeoff procedures.