Flight levels are standardized pressure altitudes used by aircraft to maintain safe separation of air traffic at various altitudes. They are expressed in hundreds and are based on the International Standard Atmosphere pressure setting of 1013.2 Hpa (or 29.92 InHg). This standardization simplifies communication and enhances situational awareness, enabling effective air traffic management.

Flight levels are essential for maintaining Reduced Vertical Separation Minima (RVSM), a fundamental aspect of air traffic management. Pilots switch to flight levels during ascent and revert to local atmospheric pressure settings during descent, determined by aviation authorities.

During ascent, aircraft reach the transition altitude, which varies across regions. During descent, they reach the transition level, which is specified on standard arrival charts or instrument approach charts used for landings. Understanding flight levels and how aircraft measure altitude is crucial for maintaining safe and efficient air travel, ensuring consistency and uniformity in altitude reporting. The concept of flight levels is a testament to the collaborative efforts of pilots, air traffic controllers, and aviation authorities in creating a framework that prioritizes the safety and well-being of all passengers.