IFRS19 comes into effect on 01/01/19. It is a new financial requirement that eliminates most rentals and leases from off balance sheet accounting. This will impact on companies credit ratings, borrowing costs and over gearing. I am confident there may be some major issues for the Qantas Group if the rumours about their accounting practices are true.
So that is why all these JQ A320's are coming off lease and being purchased by QF (Just have to look at the weekly CASA registration reports)