Re query on ATPL and degree standard: When I did my Brit ATPL over 50-years ago I seem to recall the written exams being held over 5-days and 13 subjects. The only aid you were allowed was a pocket slide-rule, and there were no multi-choice papers; it was all hand-written. They even had Navigators licences in those days, which were even tougher than the ATPL. I considered this question myself in my young days and went off to university as a mature student to study aeronautical engineering - and found that the ATPL studies were no more than first year studies for a BSc student. Even so, I would suggest the ATPL is a good primer.