| 1 | TTI | Aero Attie, S.A. de C.V. | Callsign: Aero Attie, | MEX | AVCODES |
| 2 | TTI | TRANSKENTUCKY RAILROAD | | | PWRC |
| 3 | TTI | Transkentucky Transportation | | USA | TRAFFIC |
| 4 | TTIB | TOTAL TRANSPORT INC | | | SCAC4 |
| 5 | TTIC | TRI-S TRUCKING, INC | | | SCAC1 |
| 6 | TTIC | TRANSIT TEC INC | | | SCAC4 |
| 7 | TTID | TUNDRA TRANSPORT INC | | | SCAC4 |
| 8 | TTIE | TIGER TRANS INC | | | SCAC4 |
| 9 | TTIK | TRANSPORTES INTERNACIONALES KARVI S | | | SCAC4 |
| 10 | TTIL | TRANSPORTES INTERNACIONALES ZALDIVA | | | SCAC4 |
| 11 | TTIM | T & T IMPORTS INC | | | SCAC4 |
| 12 | TTIO | TRANSITION LLC | | | SCAC4 |
| 13 | TTIP | TRAILER TRANSIT INC | | | SCAC4 |
| 14 | TTIS | Transkentucky Transportation R.R. Co., Inc. | 1/1980; added 4/1980; eliminated 7/1980 | | NAKINA |
| 15 | TTIS | Transkentucky Transportation Co., Inc. | 1/1980; added 7/1980; 1/1994; eliminated 7/1998; 7/2000-7/2005 | | NAKINA |
| 16 | TTIS | Transkentucky Transportation R.R. Co., Inc. | 1/80; added 4/80; eliminated 7/80 | | NRHS |
| 17 | TTIS | Transkentucky Transportation Co., Inc. | 1/80; added 7/80; 1/94; eliminated 7/98; 7/2000 | | NRHS |
| 18 | TTIS | TRANSKENTUCKY TRANSPORTATION RAILROAD, INC. | | | PWRC |
| 19 | TTIS | Transkentucky Transportation Railroad | | | RSRV |
| 20 | TTIT | TIGER TOOL INTERNATIONAL INCORPORAT | | | SCAC4 |
| 21 | TTIU | MASTERS GLOBAL LOGISTICS, INC. | | ROK | BIC |
| 22 | TTIU | THAILAND TANTALUM INDUSTRY CORPORATION LTD | | | PWRC |
| 23 | TTIU | Thailand Tantalum Industry Corporation Limited | | | RSRV |
| 24 | TTIV | TUCSON TRANSPORT INC | | | SCAC4 |
| 25 | TTIW | T T I INC | | | SCAC4 |
| 26 | TTIX | Transcontinental Transport, Inc. | added 4/1956; 10/1957-4/1961; eliminated 4/1965 | | NAKINA |
| 27 | TTIX | North American Car Corp. | added 4/1965; 7/1965-1/1980; eliminated 1/1984 | | NAKINA |
| 28 | TTIX | General Electric Railcar Services Corp. | added 1/1984; eliminated 4/1989 | | NAKINA |
| 29 | TTIX | TTX Co. | added 7/2007 | | NAKINA |
| 30 | TTIX | TTX Co. (no definition) | added 7/2007 | | NAKINA |
| 31 | TTIX | Transcontinental Transport, Inc. | 10/57-4/61; eliminated 4/65 | | NRHS |
| 32 | TTIX | North American Car Corp. | added 4/65; 7/65-1/80 | | NRHS |
| 33 | TTIX | General Electric Railcar Services Corp. | eliminated 4/89 | | NRHS |
| 34 | TTIX | *(NATX) RETIRED 08-22-92 ATP [GEN. ELECTRIC RAILCAR SERVICE; NORTH AMERICAN CAR CORP.; TRANSCONTINENTAL TRANSPORT, INC.] | | | PWRC |
| 35 | TTIX | *TRITON TRANSPORTATION, INC. | | | PWRC |
| 36 | TTIX | +TTX COMPANY {TRAILER TRAIN COMPANY} | | | PWRC |
| 37 | TTIX | Trailer Train (TTX Corporation) | | | RSRV |
| 38 | TTIX | TTX COMPANY | | | SCAC4 |
| 39 | TTIY | TRANSPORTATION TECHNOLOGY INC | | | SCAC4 |
| 40 | TTIZ | TANDEM TRANSPORT INCORPORATED | | | PWRC |
| 41 | TTIZ | Tandem Transport | | | RSRV |
| 42 | TTIZ | TANDEM TRANSPORT INC | | | SCAC4 |
