The U.S. aircraft register, updated daily
Who holds what · as the FAA records the name

Twentieth Century Aircraft CO

Named as the FAA publishes it on its approvals.

Holds 1 approved modification, most of them for the Douglas C-54. FAA spelling: Twentieth Century Aircraft Co.

Approved modifications 1 · newest first

Douglas C-54 1
1960-01-01SA4-372 · CO and smoke detection system in belly baggage compartments. · DC-4, C54-DC Series

Source: FAA Dynamic Regulatory System (type certificate data sheets, supplemental type certificates, parts manufacturer approvals, technical standard order authorisations). An organisation's name is as the FAA spelled it on each record; related spellings are separate pages.