FL350 refers to a flight level of 35,000 feet above sea level, commonly used in commercial aviation. This altitude is often chosen for cruising because it allows aircraft to avoid most weather disturbances and turbulence, providing a smoother flight experience. At FL350, aircraft can also take advantage of more efficient fuel consumption due to thinner air, which reduces drag. Pilots and air traffic controllers use this designation to communicate altitude clearly, ensuring safe separation between different flights in the airspace.