What is a primary eligibility requirement to obtain a commercial pilot certificate?

To obtain a commercial pilot certificate, one of the primary eligibility requirements is that the individual must hold a private pilot certificate. This requirement ensures that the applicant has already demonstrated foundational flying skills, knowledge, and competency, which are critical for advancing to the responsibilities associated with commercial flying. Attaining a private pilot certificate involves completing necessary flight training, passing written exams, and successfully performing flight maneuvers, which establishes a baseline level of aviation knowledge and experience.

The other options do not reflect the requirements set forth by the regulations governing commercial pilot certification. For example, the age requirement for a commercial pilot is at least 18 years old, not 16. A university aviation program, while beneficial, is not a mandatory requirement for certification; many pilots achieve their commercial status through other training avenues. Lastly, a valid driver's license is not a prerequisite for holding a commercial pilot certificate. Thus, the correct answer highlights the essential step of already possessing a private pilot certificate as a foundational requirement for advancing to commercial pilot privileges.