A jetliner is an airliner powered by jet engines (usually of the turbofan type). Most modern long-distance air travel is conducted with jetliners, although the fleets of many airlines include a number of smaller turboprop aircraft, typically used for shorter flights to provincial towns, island communities, or airports where topography or adjoining development limits the runway length.

The Boeing 707, Convair 880, De Havilland DH106 Comet, Douglas DC-8, Sud Aviation Caravelle and Tupolev Tu-104 of the 1950s represented the first generation of jetliners and considerable national prestige was attached to developing prototypes and bringing these various designs into service. There was a strong nationalism in purchasing policy, such that the Boeing and Douglas products became closely associated with Pan Am, whilst BOAC ordered Comets, Aeroflot used Tupolevs, and Air France introduced Caravelles.

The Boeing Company achieved numeric supremacy, perhaps partly due to its origins as a well-funded military project, the KC-135 Stratotanker and versions of the 707 remain operational - mostly as tankers or freighters. The basic configuration of the Boeing, Convair and Douglas aircraft, with widely spaced podded engines underslung on pylons beneath a swept wing, proved to be the prevalent arrangement by 1980 and was most easily compatible with the large-diameter high-bypass turbofan engines that subsequently prevailed for reasons of quietness and fuel efficiency. The de Havilland and Tupolev designs had engines incorporated within the wings next to the fuselage, a concept that endured only within military designs whilst the graceful Caravelle pioneered engines mounted either side of the rear fuselage. In the 1960s, when jetliners were powered by slim, low-bypass engines, many aircraft used the rear-engined configuration, such as the Boeing 727, Douglas DC-9, BAC One-Eleven, Hawker Siddeley Trident, Ilyushin Il-62 and Vickers VC-10. It survives into the 21st century on numerous Douglas DC-9 derivatives plus newer short-range jetliners built by Bombardier, Embraer and, until recently, Fokker. For business jets the rear-engined configuration is universal as on small aircraft such as these the wing is too close to the ground to accommodate underslung engines.

The DH106 Comet should not be confused with the earlier piston-engined De Havilland DH.88 racer also known as the Comet.