Small regional airlines operating in the U.S. during the 1960s and 1970s were also known as commuter airlines and were classified as such in the Official Airline Guide (OAG).
Regional airlines began by operating propeller-driven aircraft over short routes, sometimes on flights of less than 100 miles. In the early days of commercial aviation few aircraft had ranges greater than this, and airlines were often formed to serve the area in which they formed. That is, there was no strong distinction between a regional airline and any other airline. This changed with the introduction of long-range aircraft, which led to the development of the flag carrier airlines, such as British Overseas Airways Corporation and Trans-Canada Airlines. As the flag carriers grew in importance with increasing long-range passenger traffic, the smaller airlines found a niche flying passengers over short hops to the flag carrier's airport. This arrangement was eventually formalized, forming the regional airlines.
Through the 1960s and 1970s, war surplus designs, notably the DC-3, were replaced by much more capable turboprop or jet-powered designs like the Fokker F27 Friendship or 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.
Some of the original regional airlines (then known as "Local Service Airlines") sanctioned by the Civil Aeronautics Board in the 1940s and 1950s include: