I am currently looking at flights to bring my girlfriend and her 7yo son to Perth for a holiday next April.
Researching the available fares on the internet has been quite enlightening, as follows:
Thai Airways Udon - Bangkok - Perth return about TBH56,000 (AUD$2000)

Using Air Asia or Nok from Udon to Bangkok, and then Thai to Perth, about TBH3,000 cheaper

Singapore Airlines Bangkok - Sing - Perth return, plus Air Asia/Nok Udon to Bangkok, about TBH52,000

Tiger Air Udon to Singapore return, then Singapore Airlines to Perth and back, TBH37,000


All the fares are economy for 1 adult plus 1 child. I imagine the last option would work equally well for other Australian cities ex Singapore.
Let's hope the Tiger experiment works over the long term.
jack