Depends, Modular you can pick and mix as it were. For example, feel to correct me if I am wrong, in order to sit ATPL written exams you only need a ICAO PPL, so if you want, you can go to a sunny climate, get your PPL there and then start your written.
Well it was like that several years ago, for example I know of many who went to the USA and got a FAA PPL, 1 written exam.
All are now flying Jets for major and one or two cases Legacy Airlines.