I'm afraid that there is no way that a JAA ATPL equates to a degree, either in depth or length of study. It's a simplification, I know, but ATPL ground studies are a matter of learning pat answers to specific, known, and often over-simplified questions. Understanding the subjects is a bonus, but not essential to passing the exams. In fact, a real understanding of all the subjects covered in the ATPL would take many years of study - and would most certainly be worthy of degree status!
Scroggs