Civil Aeronautics Board

The Civil Aeronautics Board (CAB) was an independent agency of the federal government of the United States, formed in 1940 out of the prior Civil Aeronautics Authority (the Authority) and abolished in 1985, best known for tight economic regulation of the US airline industry through 1978. The CAB's regulatory powers originated in the 1938 Civil Aeronautics Act, which created the Authority and two other bodies. A 1940 amendment re-arranged 1938 Act duties, with economic regulation going to the CAB and most air safety/operational matters going to the Civil Aeronautics Administration (CAA), a significant exception being air accident investigation which went to the CAB. The 1958 Federal Aviation Act amended the 1938 Act, with some non-economic CAB functions split off. The 1966 Federal Transportation Act gave CAB's accident investigation duties to the newly-created National Transportation Safety Board (NTSB).

In 1977 the Air Cargo Deregulation Act substantially reduced the CAB's ability to regulate air freight. The Airline Deregulation Act of 1978 substantially reduced the CAB's passenger airline powers effective 1979, phasing out remaining powers until 1985 abolishment. Residual economic regulatory powers went mostly to the Department of Transportation, some to the US Postal Service. The period 1938–1978, when CAB/Authority economic power was at its height, is known as the regulated era of the US airline industry.

While the CAB is best known for economic regulation of airlines, its powers extended to related companies characterized as indirect air carriers, such as air freight forwarders, a significant industry of its own. Further, some airlines were able to escape most CAB regulation, while the CAB exempted still others from regulation. CAB regulations resulted in a complex system of many different types of airlines defined by different regulatory limits, as outlined below.