FL220 refers to an altitude of 22,000 feet above sea level, commonly used in aviation. The "FL" stands for "Flight Level," which is a standard way to measure altitude in aviation, particularly when flying at higher altitudes. At this level, aircraft are typically cruising, allowing for efficient travel over long distances. Flying at FL220 is often used for commercial flights, as it provides a balance between fuel efficiency and air traffic management. Pilots must adhere to specific regulations and air traffic control instructions when operating at this altitude to ensure safety and avoid collisions with other aircraft.