A frozen ATPL means a pilot has completed all ATPL theoretical exams along with a CPL and required ratings but has not yet reached the full flight experience (about 1,500 hours) needed for a full ATPL. It allows the pilot to work as a first officer in airlines while gaining experience. A full ATPL, on the other hand, grants captain authority and requires higher flight hours. In career terms, a frozen ATPL is a stepping stone, while a full ATPL is the final, senior-level certification.