A regional airliner, commuter airliner or feeder liner is a small airliner that is designed to fly up to 100 passengers on short-haul flights, usually feeding larger carriers' airline hubs from small markets. This class of airliners is typically flown by the regional airlines that are either contracted by or subsidiaries of the larger airlines. Regional airliners are used for short trips between smaller towns or from a larger city to a smaller city. Feeder liner, commuter, and local service are all alternative terms for the same class of flight operations.

To keep short routes economical, airlines preferred using second hand aircraft than costlier new aircraft. Older aircraft were put into short haul service as they were replaced by new longer-range designs.

Propeller aircraft of larger airlines were transferred to smaller airlines. Examples included the De Havilland Dragon Rapide biplane and the Douglas DC-3s, in large surplus after the war, which the aircraft manufacturers wanted to replace.

The first piston-powered airliners with 40 seats were the Martin 2-0-2s (introduced in 1947) and Convair CV-240s (1948).

The first turboprop powered aircraft emerged like the Vickers Viscount (75 seats, introduced in 1953) and Fokker F27 (44–52 seats, 1958). Some smaller turboprop airliners were developed in the 1960s like the British Shorts Skyvan (19 seats, 1963), and French Nord 262 (29 seats, 1964) or Brazilian Embraer EMB 110 Bandeirante (1973). This "hand-me-down" process of supplying aircraft continued with designs like the Convair 440 and Douglas DC-6 also serving in this role while the first jets were introduced.

By the mid-1950s, demand for even more economical designs led to the production of the first custom feeder liners. These were almost always turboprops, which had fuel economy on par with piston engine designs, but had far lower maintenance costs. Often, the time between engine overhaul periods was five times that of the best piston engines. Early examples of these designs include the Fokker F27 Friendship, Avro 748, and Handley Page Dart Herald.

These designs were so successful that it was to be many years before newer designs bettered them enough to make it worthwhile in terms of capital investment to develop. Among the first purpose-built airliners developed for the CAB sanctioned local-service airlines in the US, the predecessors of the modern regional airliner industry; was the interim and custom-built Fairchild F-27/FH-227's for the needs of these smaller but expanding airlines of the late 1960s.

There were a few other exceptions, generally tailored to more specific roles. For instance, the Handley Page Jetstream (first flight in 1968) was intended for fewer passengers at much higher speeds, displacing smaller designs like the Beechcraft Queen Air. The Fairchild/Swearingen Metro (developed from the original Queen Air through a number of stages) filled a similar niche.