Qantas is Australia's largest airline. Qantas was founded in Winton, Queensland, on 16 November 1920 as Queensland and Northern Territory Aerial Services Limited by Paul McGinness, Sir Hudson Fysh and Sir Fergus McMaster, the latter of whom was chairman. Arthur Baird was employed as a chief aircraft engineer. McGinness left QANTAS for other interests, and Hudson Fysh remained with the company as General Manager & Managing Director. He retired as Sir Hudson Fysh KBE DFC, Chairman of QANTAS in 1966.

Initially, the airline operated taxi and joy flights, as well as airmail services subsidised by the Australian government, linking railheads in western Queensland. Between 1926 and 1928 Qantas built several aircraft in Longreach and made the inaugural flight of the Royal Flying Doctor Service of Australia, departing from Cloncurry. Qantas Empire Airways Limited (QEA) was formed by Qantas and Britain's Imperial Airways in 1934. They flew internationally from May 1935, when the service from Darwin was extended to Singapore. As operations expanded with flying boat services, World War II disrupted air travel until 1943. In 1947, QEA was nationalised, with the Australian Labor government buying the shares. In the same year, the airline took delivery of Lockheed L-749 Constellations and these took over the trunk route to London. In 1958, Qantas became the second round-the-world airline, flying Super Constellations westward from Australia to London through Asia and the Middle East.

In 1956, Qantas ordered the Boeing 707-138 jet airliner, and the first was delivered in June 1959. The first jet service operated by Qantas was on 29 July 1959 from Sydney to San Francisco via Nadi and Honolulu. On 5 September 1959 Qantas became the third airline to fly jets across the North Atlantic. In 1966, the airline diversified its business by opening the 450-room Wentworth Hotel in Sydney. In 1967, the airline placed orders for the Boeing 747, and Qantas Empire Airways changed its name to Qantas Airways. When Cyclone Tracy devastated the town of Darwin at Christmas 1974, Qantas established a world record for the most people ever embarked on a single aircraft when it evacuated 673 people on a single Boeing 747 flight. In March 1979, Qantas operated its final Boeing 707 flight from Auckland to Sydney, and until the delivery of the first Boeing 767 in 1985 became the only national airline in the world to have a fleet consisting of a single aircraft type.

The Boeing 747 fleet was upgraded from 1989 with the arrival of the new Boeing 747-400 series. The delivery flight of the first 747-400 was a world record for commercial aircraft, flying the 18,001 km (11,185 mi) from London to Sydney non-stop. The Australian Government sold the domestic carrier Australian Airlines to Qantas in August 1992. This provided Qantas access to the Australian domestic market for the first time in its history. Qantas was privatised in two stages, first by a sale of 25% to British Airways in 1993 and the remaining 75% by public float in mid-1995. Qantas ordered twelve Airbus A380-800s in 2000 and was soon the third airline to receive A380s, after Singapore Airlines and Emirates. The airline created a new cut-price subsidiary airline, Jetstar Airways after Virgin Blue expanded in October 2001. On 13 December 2004, the first flight of Jetstar Asia Airways took off from its Singapore hub to Hong Kong, marking Qantas' entry into the Asian cut-price market.

Before 29 October 2011, Qantas operated a significant number of international flights into and out of Singapore Changi, Auckland Airport, Brisbane Airport, Los Angeles International and London Heathrow airports. Qantas has been one of the most profitable airlines in the world. In 2008, the first Qantas Airbus A380 was handed over by Airbus at a ceremony on 19 September. The first route for the A380 was Melbourne to Los Angeles.

Qantas Airways Limited ( KWON-təs) is the flag carrier of Australia and its largest airline by fleet size, international flights and international destinations. It is the world's third-oldest airline still in operation, having been founded in November 1920; it began international passenger flights in May 1935. Qantas is an acronym of the airline's original name, Queensland and Northern Territory Aerial Services, as it originally served Queensland and the Northern Territory, and is popularly nicknamed "The Flying Kangaroo". Qantas is a founding member of the Oneworld airline alliance.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 per cent share of the Australian domestic market and carried 14.9 per cent 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, 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.