From their wed site:
Unfortunately flying into Wings Over Illawarra will not be an option in 2015.
Unfortunately due to the large amounts of rainfall experienced over the latter part of April, the grass areas of WOL airport are completely unusable, and with more rain predicted before the event the likelihood of it drying enough to allow access is absolutely zero.
This has resulted in all display aircraft, both static and flying having to be relocated to hardstand areas only. This combined with runway 08/26 remaining open to safeguard against the westerly winds of last year has left no space whatsoever for the parking of visiting aircraft.
We apolgise for this inconvenience, but unfortunately there simply is no solution to this problem.