Commercial aeroplanes typically cruise at approximately 35,000 feet (roughly 10,700 meters) because it is the "sweet spot" for aerodynamic and engine efficiency. At this altitude, the air is much thinner than at sea level, which significantly reduces aerodynamic drag, allowing the plane to fly faster while consuming less fuel. Furthermore, jet engines (turbofans) operate most efficiently in the cold, thin air of the lower stratosphere. Flying at this height also keeps the aircraft above the troposphere, where most turbulent weather, storms, and heavy clouds occur, resulting in a smoother ride for passengers. Additionally, this altitude provides a critical safety margin; if an engine fails, the pilot has more time and "gliding distance" to find a suitable emergency landing site. By 2026, flight levels are also strictly managed to maintain vertical separation from other aircraft, and 35,000 feet remains a standard cruising level for medium-to-long-haul jets optimized for fuel economy and speed.