Once you take out the loan you have to start paying it back, so I'd get the exams done first then borrow the money. ATPL exams are hard if you're working full time. I had to take a month of work for each set of exams. Personally I didn't touch a plane until I'd passed them all. I think it's better to bunch the flying up together as much as possible. I put a fair bit on 0 percent cards, now working for an airline.