Historical Trends and Future Projections of Key Performance Parameters in Aircraft Design

This study presents a comprehensive analysis of historical trends and future projections for key performance parameters (KPPs) in commercial turbofan aircraft, focusing on operational empty weight to maximum takeoff weight ratio (OEW/MTOW), thrust-to-weight ratio (T/W), thrust-specific fuel consumption (TSFC), and lift-to-drag ratio (L/D). Leveraging the open-source FAST Aerobase, comprising over 400 commercial airframes and 200 engines, drawn from authoritative sources such as FAA and EASA certifications, along with enhanced regression modeling, this study systematically examines the evolution of each KPP in response to technological advancements, market demands, and regulatory constraints. The analysis reveals that TSFC improvements align closely with technological advances and primarily increases in bypass ratio enabled by core downsizing. Trends in OEW/MTOW and T/W are dominated by market-driven range, size, and regulatory factors rather than pure material or propulsion breakthroughs, which indicates limited room for further improvement without disruptive configurations. Cruise L/D improvements have been primarily enabled by wingtip devices, although they are approaching structural and regulatory limits. This work lays a robust foundation for the open-source Future Aircraft Sizing Tool (FAST), equipping designers with data-driven insights to support early-stage design decisions and providing a transparent resource for understanding the historical and technical drivers of commercial aircraft performance.