thumb|right|Airbus A340-600 wide-body airliner of Cathay Pacific, an airline based in Hong Kong

An airliner (also called Commercial Transport Planes) is a large fixed-wing aircraft with the primary function of transporting paying passengers and carrying cargo. Such planes are owned by airlines. The definition of an airliner varies from country to country, but the common definition is an aircraft with an empty weight above , with two or more engines.

History

If an airliner is defined as a plane intended for carrying multiple passengers in commercial service, the Russian Sikorsky Ilya Muromets was the first official passenger aircraft. The Ilya Muromets was a luxurious aircraft with an isolated passenger saloon, comfortable wicker chairs, bedroom, lounge and a bathroom. The aircraft also had heating and electrical lighting. The Ilya Muromets first flew on December 10, 1913. On February 25, 1914, it took off for its first demonstration flight with 16 passengers aboard. From June 21 June 23, it made a round-trip from Saint Petersburg to Kiev in 14 hours and 38 minutes with one intermediate landing. If it had not been for World War I, the Ilya Muromets would have probably started passenger flights that same year.

The second airliner was the Farman F.60 Goliath from 1919, which could seat up to 14 passengers. Approximately 60 were built. It was followed in 1923 by a less successful quad-engine Farman F.121 Jabiru.

The Ford Trimotor was an important early airliner. With two engines mounted on the wings and one in the nose and a slabsided body. It carried eight passengers and was produced from 1925 to 1933. It was used by the predecessor to TWA as well as other airlines long after production ceased. In 1932 the 14-passenger Douglas DC-2 flew and in 1935 the more powerful, faster, 21–32 passenger Douglas DC-3. DC-3s were produced in quantity for WWII and sold as surplus afterward.

The first jet airliners came in the immediate post war era. Turbojet engines were trialled on piston engine airframes such as the Avro Lancastrian and the Vickers VC.1 Viking the latter becoming the first jet engined passenger aircraft in April 1948. The first purpose built jet airliners were the de Havilland Comet (UK) and the Avro Jetliner (Canada). The former entered production and service while the latter did not. The Comet was unfortunate in that metal fatigue caused crashes.

Jets did not immediately replace piston engines and many designs used the turboprop rather than the turbojet or the later turbofan engines.

Wide-body jets

thumb|right|Airbus A330 wide-body airliner of Brazillian airline TAM Airlines thumb|right|Boeing 757 narrow-body airliner of Thomas Cook Airlines, a United Kingdom charter airline

main: Wide-body aircraft