Aircraft are becoming increasingly more fuel-efficient, driven by a combination of lightweight composite materials, advanced aerodynamics, and a new generation of high-bypass turbofan engines. Over the past two decades, aircraft like the Boeing 787 Dreamliner and Airbus A350 have redefined long-haul efficiency, offering fuel burn reductions of up to 25% compared to the aircraft they replace. As fuel remains one of the largest cost drivers for airlines, these efficiency gains play a critical role in both profitability and sustainability.