Flight schedules under partnership: The effects of capacity purchase agreements on airline schedule buffers

This study examines how capacity purchase agreements (CPAs) between major U.S. network carriers and their regional airline partners affect schedule padding practices. Using a large dataset of over 7 million flight-level observations from 2023 and distinguishing between flights operated directly by mainline carriers and those operated by regional partners under branded CPA arrangements, we assess whether CPAs incentivize airlines to pad schedules more aggressively. Results consistently show that CPA-operated flights have significantly more schedule padding than mainline-operated flights, with the effect being most pronounced in long-haul markets. These findings amplify the dual-edged nature of such partnerships: while CPAs support network connectivity and operational reliability, the systematically longer scheduled block times may reduce aircraft utilization. • This study examines CPA effects on schedule padding in the U.S. airline industry. • CPA-operated flights show significantly higher padding than mainline flights. • Delta and United exhibit greater padding, while American and Alaska show lower effects. • Padding effects are larger in long-haul markets compared to short- and medium-haul routes.