Worldwide airline network evolution between 2000 and 2023: A systematic analysis of hubs, hub links, allocations, and direct links

This study examines the evolution and structural patterns of hub networks within global air transportation systems from 2000 to 2023. By analyzing key network metrics - such as the number of hubs, hub link density, the number of allocation links per spoke, and direct links bypassing hubs - this research uncovers trends and shifts in airline network configurations over time. The analysis is based on a comprehensive, worldwide air transport dataset spanning over two decades, offering a robust foundation for identifying changes in network design and operational strategies. Full-Service Carriers (FSCs) and Low-Cost Carriers (LCCs) expanded their hubs–especially in North-East Asia–while Regional/Commuter carriers reduced theirs, presenting new logistical and financial challenges. The distinction between FSCs and LCCs has blurred, with both adopting hybrid strategies–FSCs unbundling services and LCCs incorporating premium features–driven by market demands and competitive pressures, ultimately intensifying competition and benefiting consumers. Additionally, the rise of direct links, particularly among LCCs in Western Europe and South-East Asia, reflects a shift toward efficiency and passenger-centric travel, necessitating adaptive infrastructure and sustainable practices to balance profitability and environmental considerations. Finally, our study is the first to provide empirical fits for the magnitude of network elements versus airline type and the size of the network. Finally, this study presents the first empirical quantification of network element magnitudes relative to airline type and network size, offering novel insights into the structural dynamics of global airline operations.