There is unofficial air mail in Aus. It's not a service you can request or pay for. If I send a parcel to WA or FNQ (from NSW), I have to sign a declaration sticker to say that it's safe to go via air. Most of the time the buyer has it in 3-4 days. If I send a large letter item, it just goes the slow route and can take 3-4 weeks to get to WA and FNQ.