Regional airline

A regional airline is a general classification of airline which typically operates scheduled passenger air service, using regional aircraft, between communities lacking sufficient demand or infrastructure to attract mainline flights. In North America, most regional airlines are classified as "fee-for-departure" carriers, operating their revenue flights as codeshare services contracted by one or more major airline partners. A number of regional airlines, particularly during the 1960s and 1970s, were classified as commuter airlines in the Official Airline Guide (OAG).

Decades before the advent of jet airliners and high-speed, long-range air service, commercial aviation was structured similarly to rail transport networks. In this era, technological limitations on air navigation and propeller-driven aircraft performance imposed strict constraints on the potential length of each flight; some routes covered less than 100 miles (160 km).^{[citation needed]}

As such, airlines structured their services along point-to-point routes with many stops between the originating and terminating air terminals. This system of air transportation effectively forced most airlines to be "regional" in nature, but the lack of distinction among carriers soon began to change with the 1929 launch of Transcontinental Air Transport (T-A-T) in the United States. T-A-T's transcontinental "Lindbergh Line" became America's first contiguous coast-to-coast air service, and it ushered in a new era of major airlines expanding to operate networks with large footprints. The development of long-range aircraft operated by flag carriers like British Overseas Airways Corporation and Trans-Canada Airlines further normalized the capability of "far and wide" air travel among the traveling public.

"Regional airline" is a flexible term whose meaning has changed substantially over time. What it means today is different than how it has been used in the past. For instance, in the United States, around 1960, the term “regional carrier” denoted the smaller eight of the 12 largest carriers, then known as trunk carriers (or trunk airlines or simply trunks). At the time the four biggest airlines in the United States were known as the Big Four, comprising American, United, TWA and Eastern Air Lines. The other eight trunk carriers were Braniff, Capital, Continental, Delta, National, Northeast, Northwest and Western. Since, at the time, none of these eight had a network approaching the scale of the Big Four, they were known as the regional carriers. This was despite the existence, at the time, of 13 smaller United States scheduled carriers known as local service carriers whose service was arguably far more regional than the “regional” trunks.

So when reading historical sources, it is important to understand that the term "regional airline" has migrated greatly over time. Sometimes the term has been stretched beyond the point of utility. For instance, in a 1983 article about PBA, Provincetown-Boston Airlines, both Air New England and Air Florida are described as regional airlines. At the time, Air New England was a recently failed turboprop operator in the northeast US, while Air Florida was a jet carrier flying from Florida to the northeast, to Latin America and Europe. The two airlines had little in common.

As flag carriers grew to fill the demand of long-range passenger traffic, new and small airlines found niches flying between short and underserved routes to and from major airports and more rural destinations. Through the 1960s and 1970s, war surplus designs (notably, the Douglas DC-3) were replaced by higher-performance turboprop or jet-powered designs like the Fokker F27 Friendship and BAC One-Eleven. This extended the range of the regionals dramatically, causing a wave of consolidations between the now overlapping airlines.

In the United States, regional airlines were an important building block of today's passenger air system. The U.S. Government encouraged the forming of regional airlines to provide services from smaller communities to larger towns, where air passengers could connect to a larger network.

The original regional airlines (then known as "Local service carriers") sanctioned by the Civil Aeronautics Board from 1943 to 1950 include: