Mayflower Airlines

Mayflower Airlines was a small United States scheduled airline founded June 22, 1935 that started operations on June 15, 1936 flying from Boston to Cape Cod, Nantucket and Martha's Vineyard on a seasonal basis before World War II.

The airline applied to be certificated on October 20, 1938 by the Civil Aeronautics Board (CAB) on the basis of operating scheduled service before the Civil Aeronautics Act of 1938.

[1] But Mayflower did not operate after September 1939, although it had CAB approval of such suspension of service.

[2][3] The fact that Mayflower was certificated by the CAB on the basis of pre-Civil Aeronautics Act scheduled service in theory made it a trunk carrier, in the same category as any other United States airline with the same basis for certification, like Continental Airlines or Braniff.

But Mayflower never actually operated as such, making it an odd edge case.