How is the phrase “flight level” typically denoted in aviation?

The phrase "flight level" in aviation is correctly denoted using the term "FL" followed by the altitude in hundreds of feet. This standard convention is utilized internationally and is critical in air traffic control and flight operations to ensure clarity in communication between pilots and air traffic controllers. For example, an altitude of 30,000 feet is referenced as "FL300," indicating that the altitude is 30 times 100 feet, or 30,000 feet.

This method of denotation helps maintain consistency and reduces potential confusion across different regions and among pilots of various backgrounds. It is especially important when aircraft operate at high altitudes where variations in atmospheric pressure can affect altitude readings.

Other choices lack precision or do not align with the standardized nomenclature used in aviation. Specifying altitude in meters or feet and nautical miles diverges from the accepted terminology for flight levels, which is specifically tied to pressure altitudes measured in hundreds of feet and marked with "FL."