The Lockheed Constellation ("Connie") is a propeller-driven, four-engined airliner built by Lockheed Corporation starting in 1943. The Constellation series was the first pressurized-cabin civil airliner series to go into widespread use. Its pressurized cabin enabled commercial passengers to fly well above most bad weather for the first time, thus significantly improving the general safety and ease of air travel.
Lockheed Constellation
A preserved C-121C Super Constellation, registration N73544, in flight in 2004
The first Lockheed Constellation on January 9, 1943
TWA L-749A Constellation at Heathrow in 1954 with an under fuselage "Speedpack" freight container
An airliner is a type of airplane for transporting passengers and air cargo. Such aircraft are most often operated by airlines. The modern and most common variant of the airliner is a long, tube shaped, and jet powered aircraft. The largest of them are wide-body jets which are also called twin-aisle because they generally have two separate aisles running from the front to the back of the passenger cabin. These are usually used for long-haul flights between airline hubs and major cities. A smaller, more common class of airliners is the narrow-body or single-aisle. These are generally used for short to medium-distance flights with fewer passengers than their wide-body counterparts.
A United Airlines Boeing 737 (foreground) and a Virgin America Airbus A320 (background), two of the world's most widely used airliners
Sikorsky Ilya Muromets
The Douglas DC-3 appeared in 1935
Prototype of the de Havilland Comet in 1949, the first jet airliner in the world