I remember doing some research on 20th Century in the past but can't find my bookmarks of the results. However I did find this collection as a start.
The earliest reference:
….For a brief period in the 1940’s, three Charlotte-based airlines took to the air, providing passenger and freight services, having a great time, and demonstrating the potential of aviation to North Carolina. Glenn Shaver grew up on a farm in Ohio. He worked as a co-pilot for Eastern Airlines, a test pilot for B-24’s during the war, and then came to Charlotte as a pilot for State Airlines. He became friends with his Church of God minister, Rev. Chris A Bachman. The two men started Twentieth Century Airlines in mid-1946, with Shaver as general manager and Bachman as president. Bachman sold his family farm in Illinois to finance the venture.
Jack Tadlock and Leon Fox were the first pilots hired. Other pilots included Joe Gibson, Johnnie Berryhill, George Wilson, Harry Whipple and Joe Fickland. Wendall Karr became superintendent of maintenance. The airline operated from a small, former army hanger on the western side of the airport, and most repairs were made outside on the ramp.
Twentieth Century purchased three war-surplus C-47’s and converted them into passenger DC-3’s. This enabled the airline to begin thrice weekly, scheduled flights from Charlotte to Chicago Midway Airport with stops in Hickory, Tri-Cities and Cincinnati.
The airline organized charter flights, including numerous ones carrying Puerto Ricans from San Juan to New York. Twentieth Century’s most colorful activity was barnstorming at air shows on the East Coast. One stunt was landing a J-3 Cub airplane on a rack attached to Shaver’s moving Pontiac.
The biggest spectacle was Shaver flying a complete round loop in a DC3, the only person to achieve such a feat. The airline performed this loop 15 to 25 times. How was this achieved? "A secret of permission," says Shaver, "and proper timing." Shaver knew how to please the crowds. "He always carried the image of being straight off the farm," says Karr former Superintendent of maintenance.
Twentieth Century did not apply for the CAB certification to be a local service airline. But when Piedmont started flying daily to Tri-Cities and Cincinnati in early 1948, this led to cancellation of Twentieth Century’s Charlotte-Chicago flights and the beginning of financial problems.
By the spring of 1950, Shaver and Bachman found a solution. Twentieth Century merged with Parks Airlines of East St. Louis, contributing the three DC-3s. Both Shaver and Karr moved to St. Louis.
Then the assets of Twentieth Century and Parks Airlines, along with the financial investment of Bachman, were key resources in organizing Ozark Airlines. Shaver became a senior pilot; both he and Bachman joined Ozark’s board of directors. Ozark was one of the newly formed feeder/regional airlines that succeeded.
http://www.iidbs.com/ozark/19990506.htm
Then it seemed to be re-invented:
"
Twentieth Century Airlines, Inc., was issued a letter of registration as a large irregular air carrier by the Civil Aeronautics Board in 1947. For some reason, beginning in 1951 it conducted its business under the name of North American Airlines. On March 3, 1952, it amended its articles of incorporation so as legally to change its name to North American Airlines, Inc. By letter dated March 11, 1952, it requested the C.A.B. to reissue its letter of registration in the new corporate name."
http://openjurist.org/351/us/79/american-airlines-v-north-american-airlines
http://www.flightglobal.com/pdfarchive/view/1963/1963 - 0568.html
DC-4's:
72242 (c/n 10347/DC78) bought by Western Airlines in 1946, registered as N88784. Bought by American Airlines in 1947. Bought by Australian National Airlines Nov 25, 1948 registered as VH-ANG, named "Palana". Bought by Twentieth Century Airlines Apr 23, 1958 and registered N5519V. Bought by Seven Seas Airlines Aug 1959 named "Indian Ocean". W/o when crashlanded gear up 12 km from Nagpur, India Mar 22, 1961 after engine problems.
72243 (c/n 10348/DC79) bought by American Airlines in 1946 and registered as N90441 named "Flagship Rainbow One". Bought by Israeli AF May 15, 1948 and registered 1802. Transferred to El Al Dec 15,1948 and registered 4X-ACB. Bought by California Aircraft Corp Feb 1949 and registered N90441. Leased by El Al Feb 1950. Returned to Hemisphere Air transport Apr 1950. Bought by Twentieth Century Airlines in 1959, bought
by Hemisphere Air Transport in 1955. Bought by REAL SA Oct 1956 and registered PP-YRO. Bought by Loide Aer Nacional Jan 12, 1958 and registered PP-LEW. To VASP Jan 1962. DBR at Santos Dumont Airport, Rio de Janeiro, Brazil Nov 6, 1968 when crew forgot to lower the landing gear. Broken up Sep 1970.
http://home.att.net/~jbaugher/1942_4.html
One QANTAS Connie (VH-EAP) gained some notoriety:
[FONT=Times New Roman, Times, serif]Entered onto U.S. Aircraft Register as N9723C[/FONT]
[FONT=Times New Roman, Times, serif]Leased to Resort Airlines - 1959 to June 1960[/FONT]
[FONT=Times New Roman, Times, serif]Stored at Oakland, California when Resort Airlines ceased operations[/FONT]
[FONT=Times New Roman, Times, serif]Leased to Twentieth Century Airlines - August 1960 to 1961[/FONT]
[FONT=Times New Roman, Times, serif]Participated in an unlimited air race meeting at San Diego, California - July 18, 1971[/FONT]
[FONT=Times New Roman, Times, serif]Was withdrawn from further pylon racing after this event and returned to storage at Burbank[/FONT]
[FONT=Times New Roman, Times, serif]Prepared for a movie role - had a 'Concorde' like nose attached & 'Global' titles added - November 1971[/FONT]
http://www.aussieairliners.org/lockheed/connie.htm
As well 20th Century found it's way into a movie of a different sort:
Cry Terror!
"James Mason plays Jim Molner, a meek family man who works as a television repairman in an electronics shop. He's duped into building a small bomb filled with RDX by the diabolical bespectacled Paul Hoplin (Rod Steiger), a former Army demolition man, who says it's for a lucrative Army contract (hard to believe any rational person being fooled by that come-on). Jim's family, his nervous wife Joan (Inger Stevens) and precious preschool daughter Patty (Terry Ann Ross), are held hostage as they are coerced to participate in an extortion plot to get half a million dollars from the 20th Century Airlines. Gang leader Paul is the mastermind behind the scheme, whose other gang members are career criminal Vince (Jack Klugman), convicted rapist Steve (Neville Brand) and the bomb planter Eileen Kelly (Angie Dickinson)."
So, while little-known and buried, 20th Century has quite a history.
IIRC there are repaints done for the MJ Connie and a DC-6 floating around out there...
Rob