Over the last year or so, Auckland Airport and its biggest customers, Air New Zealand and Qantas, have been at increasingly bitter loggerheads over the airport's multi-billion dollar redevelopment. Put simply, the airport wants to future-proof aviation in Auckland by integrating the domestic and international terminals, and while the airlines agree that's needed, they are balking at the cost, saying that ultimately, it is their customers that have to pay for the airport's grandiose plans.