FTOs will say min 5 GCSEs, but they want your money.
with an Airline you want their money. do you realy think they will rather have someone who has done GCSEs then learnt to fly for a couple of years, rather than someone who has work experiance and a degree somewhere else, then gone into flying? who would you trust more with one of your jets?
have a search through some of the threads discussing "should i/ should i not got to university". that will give you an idea of what people are saying.