It's simple.
Qantas Frequent Flyer charges $$$$ for Woolworths, Amex, CBA, Optus, Hotels (and basically the rest of the large businesses in Australia) to be 'partners' with the program.
Those businesses pay their fees,as they assume that people who are chasing FF points will choose their business over rivals to get a 'free flight somewhere'.
The interesting question is,if FF is earning all these $$ in fees as a stand-alone business entity,does that entity in turn provide Qantas Airlines with revenue from the seats bought with FF points? That's where I start to get confused
