I checked flights from Perth no economy but business class $12,000 AUD return , even their flights from Sydney economy are very expensive, Singapore airlines now has a stranglehold on flights from Australia to Thailand , still no flights direct from Brisbane , have to fly Qantas Brisbane to Sydney then they give you 75 mins to transfer from domestic to international terminal (in this time you have to disembark Qantas jet, collect bags , shuttle bus to international terminal , check in, clear customs ) talk about fine if not impossible