The CAB regulated almost all commercial air transportation in the US, but there were some exceptions.
Air taxis The CAB chose not to regulate airlines flying "small aircraft". This was formalized in Part 298 of the Board's economic regulations, which in 1952 gave a blanket authorization for any airline operating an aircraft with a maximum gross takeoff weight of 12,500 lbs or less. Such airlines were originally known as "air taxis", later as
commuter airlines or
Part 298 carriers. Confusingly, "air taxi" was also the term by which the CAB referred to
Aspen Airways and
Wright Air Lines (after they became certificated carriers) within the CAB's taxonomy of certificated scheduled airlines (see "Airline categories" below). However, in 1972 the CAB expanded this category to include aircraft of 30 passengers or fewer, with a payload of less than 7,500 lbs. Such carriers did have to obtain
Federal Aviation Administration operational/safety certification but were otherwise able to fly wherever they pleased. The CAB would, on occasion, also exempt air-taxi or commuter operators to operate aircraft larger than the limits. For instance, in 1971, it exempted Executive Airlines and
Air New England (at that time a commuter carrier) to fly propeller aircraft up to 44 seats to expand service in New England. On five occasions, the CAB certificated former air taxi/commuter airlines to fly larger aircraft. These airlines were then regulated by the CAB like any other CAB carrier: •
Aspen Airways in 1967 •
TAG Airlines in 1969 •
Wright Air Lines in 1972 •
Air New England in 1974 •
Air Midwest in 1976
Intrastate airlines An airline that restricted flying to within one state and took other steps to minimize participation in interstate commerce could avoid CAB regulation and fly as an
intrastate airline. In the case of air taxis, the CAB chose not to regulate. In the case of intrastate airlines, it was legally unable to. Restriction of flying to a single state was not sufficient to avoid CAB regulation; the additional measures to avoid interstate commerce were critical. Furthermore, flying within a single state was generally interpreted strictly. An aircraft flying outside the boundaries of that one state could trigger CAB authority, including, in the case of Hawaii, flying overwater between the islands, which was upheld in court as being intrinsically interstate commerce because the Federal government had domain over the seas. Note that the Federal government, while not providing economic regulation over intrastate carriers, did regulate them from an operational/safety standpoint. For those purposes intrastate airlines were regulated by the
Federal Aviation Administration just like any other carrier.
Uncertificated carriers in 1958
Uncertificated carriers, known by a variety of names over time, such as
contract carriers or
Part 45 carriers, were airlines which escaped CAB regulation by not being
common carriers - in other words, they did not hold themselves out to the public as a carrier.
Zantop Air Transport was an example of such a company, flying aircraft on behalf of the US automakers on a private basis (before it acquired a supplemental certificate in 1962). "Part 45" was a reference to the then Civil Aviation Regulations under which the then
Federal Aviation Agency regulated the operations/safety of such non-common carrier operators. Over time, the Civil Aviation Regulations (subsequently the
Federal Aviation Regulations) changed. Instead of Part 45, such uncertificated carriers were moved to being regulated under Part 42. They then became known as
Part 42 carriers. Finally, the regulations were completely revamped, with most commercial operations moved to Part 121. Such operators were then known as
Part 121 commercial operators or simply just
commercial operators. A prominent example of such a carrier was
Zantop International Airlines (ZIA), which started in 1972 as a Part 121 commercial operator, uncertificated by the CAB. The CAB regularly enforced its powers against uncertificated carriers engaged in activities the CAB saw as making them common carriers. For instance, in February 1961, they issued a cease-and-desist order to, among others, Trans Global Airlines, Inc., aka Golden State Airlines, a Part 45 carrier, for carrying passengers to the Dunes Hotel in Las Vegas for "free". The fact that transportation was provided as part of the cost of accommodation did not make the airline any less a common carrier, and therefore guilty of providing interstate air transportation without a CAB certificate. The results of such investigations were not necessarily a foregone conclusion. In 1976, the CAB ended a long investigation by deciding ZIA was, in fact, not a common carrier (and thus did not require certification), going against the decision of its own administrative law judge. Ironically, this happened only a year before ZIA separately applied for and received certification as a supplemental air carrier. Air travel clubs were membership organizations, nominally private, that had their own aircraft and ran trips for members. In 1968, the FAA instituted Part 123 of the
Federal Aviation Regulations under which air travel clubs had their own operational requirements. Starting in the early 1970s, the CAB went after some of the largest air travel clubs for being de-facto common carriers. In 1973, it shut down Voyager 1000, a large Indiana-based air travel club. Voyager, which had a fleet comprising a
Boeing 720, two
Lockheed Electras and some piston aircraft and its own terminal at
Indianapolis Airport, unsuccessfully appealed to the federal courts. The chief pilot of Voyager was
George Mikelsons, who left to found what later became
ATA Airlines. The CAB went on to shut two other large clubs in 1974 and 1975. Notwithstanding these enforcement actions, in November 1979 (within the first year of deregulation) there were still 11 air travel clubs operationally regulated under Part 123, though by May 1980 it had dropped to seven. ==Airline categories==