Carbon fiber-reinforced polymers (CFRPs) are extensively utilized in the aerospace industry due to their exceptional strength-to-weight ratios, enabling weight reduction and improved energy efficiency. Despite their advantages, the anisotropic properties of CFRPs result in defects, such as delamination, during drilling processes, reducing manufacturing efficiency and increasing production costs. While support plates have been employed to address such issues, existing studies have not sufficiently explored their economic and environmental implications, nor have they evaluated the potential of novel materials like cork. This study introduces a novel machining economics model tailored for CFRP drilling, integrating defect suppression, energy consumption, and production costs into a unified framework. Furthermore, this research uniquely explores cork as a support plate material, which has not been previously studied in the context of CFRP drilling. Experimental analyses demonstrate that cork achieves a 12.45% reduction in delamination and lowers overall drilling costs to 87.39% of those incurred without support plates. These findings establish cork as the most sustainable and cost-effective support plate material, while the proposed model provides a comprehensive method for evaluating machining quality and sustainability. By integrating a novel machining economics model and introducing cork as a support plate material, this study offers a practical solution to enhance cost-efficiency, defect suppression, and sustainability in aerospace manufacturing.