I'm going to assume you are searching for business class availability. Delta Skymiles can be used for V Australia redemptions for 150k roundtrip. Qantas also has some availability for this summer although the odds of finding a flight on your specific dates are very slim. If aiming for Qantas, then AAdvantage is the way to go. I just booked a trip to Australia flying V Australia for the first time over the holidays.