The increasing complexity of aerospace systems requires development processes that balance agility with stringent safety and certification demands. This study presents an empirically validated Scrum-based Agile framework tailored for DO-178C compliant, safety-critical aerospace software. The framework adapts core Scrum roles, artifacts, and events to meet certification, verification, and independence objectives. Key enhancements include a multi-disciplinary product ownership model, dual compliance-and-functionality acceptance criteria, independent testing and documentation teams, and dedicated certification liaisons. The approach was evaluated through two comparable aerospace projects-one using the customized Agile process and the other a traditional Waterfall model. Results showed significant improvements: a 76% reduction in Total Effort per Requirement, 75% faster Defect Detection, 78% faster Defect Resolution, and over 50% lower Defect Density, while maintaining full compliance with DO-178C Design Assurance Level A. These findings demonstrate that Agile practices and regulatory compliance can coexist effectively when supported by disciplined tailoring and proactive engagement with certification authorities. The study also notes challenges, including increased V&V effort due to recurring Sprint activities and refactoring inherent to iterative development. Nonetheless, it identifies substantial opportunities for further gains through workflow automation, CI/CD practices, and automated documentation, verification, and configuration management. Future research should expand validation of this framework across the aerospace domain and other safety-critical industries with similar certification requirements.