| 1 | USC | US Check Airlines | Callsign: Starcheck, Name changed to AirNet Systems, Inc. | USA | AVCODES |
| 2 | USC | AirNet Systems, Inc. | Callsign: Starcheck, Name changed to Airnet II, LLC. Name changed from US Check Airlines, | USA | AVCODES |
| 3 | USC | AirNet II, LLC | Callsign: Star Check, Name changed from AirNet Systems, Inc. Name changed from US Check Airlines, | USA | AVCODES |
| 4 | USC | US Check Airlines | | | ICAO1 |
| 5 | USC | UNITED STOCKYARDS CORP. | | | PWRC |
| 6 | USCC | USCS CHEMICAL CHARTERING LLC | | | SCAC4 |
| 7 | USCE | US OCEAN LLC | | | SCAC4 |
| 8 | USCF | USCA FORWARDING - SEABELL EXPRESS I | | | SCAC4 |
| 9 | USCG | USC GROUP INC. | | | SCAC1 |
| 10 | USCG | U S PORT SERVICES INC | | | SCAC4 |
| 11 | USCG | United States Coast Guard | | USA | TRAFFIC |
| 12 | USCH | USS CHARTERING LLC | | | SCAC4 |
| 13 | USCI | USCT INC | | | SCAC4 |
| 14 | USCJ | USG SERVICES LLC | | | SCAC4 |
| 15 | USCK | US PACIFIC TRANSPORT INC | | | SCAC4 |
| 16 | USCP | UNITED STATES COLD STORAGE INC | | | SCAC4 |
| 17 | USCR | UNITY SHIPPING CO LTD | | | SCAC4 |
| 18 | USCT | U S CONTRACT TRUCKING INC | | | SCAC4 |
| 19 | USCU | UNION STEAM SHIP CO. OF NZ LTD. | | | PWRC |
| 20 | USCU | Union Steam Ship of NZ | | | RSRV |
| 21 | USCU | CP SHIPS | | | SCAC4 |
| 22 | USCV | UNITRANS | | | SCAC4 |
| 23 | USCX | United States Coal & Coke Co. | 8/1920-7/1932 | | NAKINA |
| 24 | USCX | United States Tank Car Corp. | added 10/1972; eliminated 1/1975 | | NAKINA |
| 25 | USCX | William G. Simon, Trustee | added 1/1975; 1/1975; eliminated 7/1975 | | NAKINA |
| 26 | USCX | William G. Simon | added 7/1975; 1/1980-7/2000; eliminated 7/2003 | | NAKINA |
| 27 | USCX | United States Tank Car Corp. | added 10/72; eliminated 1/75 | | NRHS |
| 28 | USCX | William G. Simon, Trustee | added 1/75; 1/75; eliminated 7/75 | | NRHS |
| 29 | USCX | William G. Simon | added 7/75; 1/80-7/2000 | | NRHS |
| 30 | USCX | WILLIAM G. SIMON TANK CAR MANAGEMENT [UNITED STATES TANK CAR CORP.; UNITED STATES COAL & COKE CO.] | | | PWRC |
| 31 | USCX | William G. Simon | | | RSRV |
| 32 | USCY | USACYC TRANSPORT | | | SCAC4 |
| 33 | USCZ | U. S. REDUCTION COMPANY, INC. | | | PWRC |
