Wearing a somewhat spartan colour scheme, Curtiss C-46 N1698M (c/n 22576) of Southern Air Transport is seen here in the late 1950s at Coolidge International Airport on the island of Antigua in the West Indies. This non-sked went on to become famous as a not-so-clandestine tool of the USA’s Central Intelligence Agency (CIA).

American Air Export & Import Co received a temporary CAB certificate to operate scheduled cargo services as Aaxico Airlines in 1957, the irregular carrier thus joining the ranks of the USA’s certificated airlines. Note the “Route 121 Airfreight Mail Express” on the fin of this C-46, denoting the airline’s eligibility to carry mail.

One of several irregular carriers which existed specifically for the purpose of transporting gamblers to casinos was Phenix Airlines, about which little is known, but which may have served Phenix City, Alabama, a 1950s nightlife hotspot. Note how the playing cards on the fin of this leased Curtiss C-46 match the N95445 registration.

Peninsular Air Transport C-46 N4761C (c/n 30465) had already seen an active life by the time it joined the airline in the early 1950s, having served with the military until 1948, operated in South America and suffered at least two forced landings.

The list of successful supplemental airlines included Johnson Flying Service of Missoula, Montana, where DC-3 N24320 is seen here in 1965. In addition to regular charter operations, Johnson was famous for providing firefighting support for the US Forest Service; its fleet included two Ford Tri-Motors and a DC-2 for “smoke jumper” operations.

Douglas DC-4 N79999 of United States Overseas Airlines (USOA), an airline renowned for providing safe, reliable charter service to military and civilian groups throughout its existence. The company was penalised for not terminating its scheduled-route operations by the CAB’s July 10, 1964, deadline, and was accordingly shut down by the CAB that September.

Douglas DC-4 N62296 (c/n 10486) in North American Airlines livery, although it was registered to 20th Century Airlines, part of the North American Airlines Agency. In April 1957 it went to Reeve Aleutian Airways, with which it was serving when it crashed at Great Sitkin Isle in the Aleutians, killing 16, in September 1959.

After a brush with bankruptcy in 1965, Overseas National Airways (ONA) went on to operate military and civilian charters with a fleet that included McDonnell Douglas DC-8s, DC-9s and DC-1 Os. This DC-8-63, N866F, named Sovereign, was acquired factory-fresh by ONA in April 1970. Sadly, ONA became a victim of deregulation.

One of the eight Boeing 377 Stratocruisers operated by Transocean, N404Q (c/n 15978) originally served with BOAC as G-AKGL Cabot from April 1950. It went to Transocean in August 1958. It was later used in the manufacture of an Aero Spacelines Super Guppy.

Boeing 727-185C N12826 of American Flyers Airline (AFA) at John F. Kennedy Airport in New York, in 1968. A successful military and civilian charter operator, AFA is perhaps best-known as the airline that transported The Beatles around the USA for their concert tours during 1964-66.

Douglas DC-6A N45500 of World Airways at Oakland, California. Under the guidance of Edward J. Daly, who bought the airline aged 27 in 1950 for $50,000, World adjusted to the USA’s changing airline industry over the years and survived both the CAB’s reign and deregulation in 1978. Sadly, the airline ceased operations in 2014.

It was rare for a “non-sked” to spend precious resources on promotional material, but this attractive artist’s impression shows a pair of Douglas DC-6As of Overseas National Airways (ONA) at a bustling airport. The airline was one of the few that survived all of the CAB’s “shake-outs” of the supplemental industry.

Saturn Airways Lockheed L100-30 ‘‘Super Hercules” N12ST. Along with ONA and AFA, Saturn was another of the lucky carriers to be represented by the National Air Carrier Association, of which Coates Lear was the president. Saturn absorbed Aaxico Airlines in 1965, before merging with Trans International Airlines in 1976.

Lockheed L-749A Constellation N101A (c/n 2518) of Standard Airways sports a pink lower fuselage, which was fitting for the company’s “Pink Cloud” service between the USA’s West Coast and Honolulu. This Connie was acquired by Standard during 1962 and saw brief service with the airline, moving on to South America in late 1963.

Lockheed L-749A Constellation N4901C (c/n 2671) of Capitol Airways in 1963. The aircraft had served with BOAC as G-ANNT, named Buckingham, from September 1954, Capitol acquiring the elegant airliner in March 1958. It later became an exhibit at the Bradley Air Museum in Connecticut until it was destroyed in a tornado in 1979.

Founded by Kirk Kerkorian as Los Angeles Air Service, Trans International Airlines (TIA) was acquired by the San Francisco-based Transamerica Corporation in 1968 and renamed Transamerica Airlines in 1979. Here TIA L-1049H Super Constellation N6925C (c/n 4853) is seen at rest between flights at Baltimore during the summer of 1965.