Operational Fuel Inefficiency in Cruise Flight: A Worldwide Geospatial Analysis

Aircraft often deviate from fuel-optimal trajectories during the cruise phase of flight, which accounts for approximately 70% of aviation fuel consumption. Deviations in horizontal route, altitude, and speed lead to excess fuel burn, increased [Formula: see text] emissions, and higher operational costs. This study provides a global assessment of cruise fuel inefficiency using trajectory data from over 32 million flights between November 2022 and November 2023. We estimate global cruise fuel inefficiency at 7.5%, representing 12.9 million metric tons of excess fuel consumption annually, with associated fuel costs and 40.7 million metric tons of [Formula: see text] emissions. Regional variation is notable, ranging from 4 to 7% in oceanic regions to 19.5% in China. Analysis of individual dimensions indicates that there is a 3.3% horizontal inefficiency from not flying the wind-optimal route, a 2.4% vertical inefficiency from not flying at the optimal altitude, and a 2.2% speed inefficiency from not flying at the optimal cruise speed.