The Boeing 377 Stratocruiser was a large long-range airliner developed from the C-97 Stratofreighter military transport, itself a derivative of the B-29 Superfortress. The Stratocruiser's first flight was on July 8, 1947. Its design was advanced for its day; its relatively innovative features included two passenger decks and a pressurized cabin. It could carry up to 100 passengers on the main deck plus 14 in the lower deck lounge; typical seating was for 63 or 84 passengers or 28 berthed and five seated passengers.
Boeing 377 Stratocruiser
The Boeing 377 production line
Berths and seating aboard a 377
A United Airlines 377 over the Golden Gate Bridge
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