With its four engines, the 747 uses vast quantities of fuel, burning through 3,800 gallons every hour. This high fuel burn amounts to 0.9 gallons used every second and 0.19 miles per gallon (mpg). This article details the Boeing 747’s mpg further, including the mpg per traveler, and how this compares to travel in a car and in modern airliners. It then delves into ongoing debates around sustainable aviation fuel to explore if aviation can be sustainable, given that all airliners burn through staggering quantities of fuel.