Qantas Airways Limited is the flag carrier of Australia and its largest airline by fleet size, international flights and international destinations. It is the third oldest airline in the world, after KLM and Avianca, having been founded in November 1920; it began international passenger flights in May 1935. 

The Qantas name comes from "QANTAS", an acronym for its original name, "Queensland and Northern Territory Aerial Services", and it is nicknamed "The Flying Kangaroo". Qantas is a founding member of the Oneworld airline alliance, along with American Airlines, British Airways, Cathay Pacific, and the now-defunct Canadian Airlines. 

The airline is based in the Sydney suburb of Mascot, adjacent to its main hub at Sydney Airport. As of March 2014, Qantas had a 65% share of the Australian domestic market and carried 14.9% of all passengers travelling in and out of Australia.

Various subsidiary airlines operate to regional centres and on some trunk routes within Australia under the QantasLink banner. Qantas also owns Jetstar Airways, a low-cost airline that operates both international services from Australia and domestic services within Australia and New Zealand; and holds stakes in a number of other Jetstar-branded airlines.

 

According to en.wikipedia