The biggest reason for flying at higher altitudes lies in fuel efficiency. The thin air creates less drag on the aircraft, which means the plane can use less fuel in order to maintain speed. Less wind resistance, more power, less effort, so to speak.

Flying at 24,000 feet (FL240) is often the "sweet spot" for regional turboprop aircraft and shorter-distance jet flights because it balances fuel efficiency with engine performance. At this altitude, the air is thin enough to significantly reduce aerodynamic drag—allowing the aircraft to fly faster and burn less fuel—yet it is still thick enough to provide sufficient oxygen for the combustion required by many turboprop engines, such as those on the Dash 8 or ATR-72. Furthermore, FL240 is usually above the "thickest" part of the weather (the lower troposphere), meaning pilots can avoid most common clouds and localized turbulence, resulting in a smoother ride for passengers. In 2026, air traffic control often assigns this altitude to "shorthaul" routes (under 300 miles) because it allows the aircraft to reach a cruise speed quickly without wasting the fuel required to climb to the "heavy jet" altitudes of 35,000 feet. It also separates smaller regional traffic from the high-altitude transcontinental corridors, ensuring a safer and more organized flow of aircraft through congested urban airspaces.