| 1 | ATT | Aer Turas Teoranta | Callsign: Aerturas, Ceased operations on 02 July 2003. | IRL | AVCODES |
| 2 | ATT | Aer Turas Teoranta | IATA: QT, Callsign: Quebec Tango, | IRL | AVCODES |
| 3 | ATT | Air Tashkent | Callsign: Hann, | UZ | AVCODES |
| 4 | ATT | Aer Turas | | | ICAO1 |
| 5 | ATT | ACE TRANSPORTATION COMPANY INC. | | | PWRC |
| 6 | ATTA | ATLANTIC TRANSFER | | | SCAC3 |
| 7 | ATTA | ANTLER TRANSPORT LLC | | | SCAC4 |
| 8 | ATTB | A & T TRANSPORT | | | SCAC3 |
| 9 | ATTC | ATLANTIC NATIONWIDE TRUCKING | | | SCAC4 |
| 10 | ATTD | ALA-TEC TRANSPORTATION INC | | | SCAC3 |
| 11 | ATTD | AUTO TRANSPORTES DIVISION PANZER S | | | SCAC4 |
| 12 | ATTE | A TRUCK & TRAILER SALES & SERVICE C | | | SCAC3 |
| 13 | ATTF | ATKINSON TRANSFER INC | | | SCAC3 |
| 14 | ATTG | ATLAS TRUCKING INC | | | SCAC3 |
| 15 | ATTH | AMERICAN TRANSBRIDGE TECHNOLOGIES I | | | SCAC4 |
| 16 | ATTI | AYCOCK, TOM TRANSPORT INC | | | SCAC3 |
| 17 | ATTI | ALL TEXAS TRUCKING INC | | | SCAC4 |
| 18 | ATTJ | ATTCO INC | | | SCAC3 |
| 19 | ATTJ | AUTOTRANSPORTES JAUMAVE SA DE CV | | | SCAC4 |
| 20 | ATTL | A & T TRANSPORTATION INC | | | SCAC3 |
| 21 | ATTM | ATLAS TRANSPORTATION CO INC | | | SCAC3 |
| 22 | ATTN | A T TRANSPORT INC | | | SCAC3 |
| 23 | ATTN | ALL THAT TRUCKING INC | | | SCAC4 |
| 24 | ATTO | ALL TOGETHER TOURS | | | SCAC4 |
| 25 | ATTP | ATC TRANSPORT LLC | | | SCAC4 |
| 26 | ATTQ | ATLANTA TRANSFER CO | | | SCAC3 |
| 27 | ATTQ | ALL TOGETHER TRANSPORTATION SYSTEMS | | | SCAC4 |
| 28 | ATTR | ATLAS TRANSPORT | | | SCAC3 |
| 29 | ATTS | ATWOOD, W E TRUCK SERVICE | | | SCAC3 |
| 30 | ATTT | ARNETT TRANSPORTS | | | SCAC3 |
| 31 | ATTV | ANDERSEN TOUR & TRAVEL SERVICE | | | SCAC3 |
| 32 | ATTV | ALL TRUCK TRANSPORTATION CO INC (DE | | | SCAC4 |
| 33 | ATTX | Trailer Train Co. | 7/1965-1/1980; eliminated 1/1992 | | NAKINA |
| 34 | ATTX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 35 | ATTX | American Turpentine & Tar Co. (, Ltd.) | 8/1920-1/1952; eliminated 4/1953; added 4/1953; 7/1954; eliminated 4/1956; added 4/1956; 10/1957; eliminated 10/1960 | | NAKINA |
| 36 | ATTX | Trailer Train Co. (FC flats equipped with 2 continuous tie-down anchor bars applied to centre sills and 2 continuous side tie-down rails. Cars are not equipped with jacks, chains, hitch and safety chains) | 4/1963-10/1968 | | NAKINA |
| 37 | ATTX | Trailer Train Co./TTX Co. (flat cars equipped with 2 continuous tie-down loops on centre sills, continuous tie-down rails on each side and bridge plates. Not equipped with hitches, chains, jacks, etc.) | 4/1970-1/1994 | | NAKINA |
| 38 | ATTX | TTX Co. (60 ft. COFC flatcars, equipped with spark shields and container latches, capable of carrying 3-20 ft. containers, or 1-40 ft. and 1-20 ft. container, fully loaded to a maximum gross weight per car (containers and lading) of 159,000 lbs.) | 7/2000 | | NAKINA |
| 39 | ATTX | American Turpentine & Tar Co., Ltd. | 4/38-10/57; eliminated 10/60 | | NRHS |
| 40 | ATTX | Trailer Train Co. | Jul-65 | | NRHS |
| 41 | ATTX | Trailer Train Co. (FC flats equipped with 2 continuous tie-down anchor bars applied to centre sills and 2 continuous side tie-down rails. Cars are not equipped with jacks, chains, hitch and safety chains) | 10/66-10/68 | | NRHS |
| 42 | ATTX | Trailer Train Co. | Apr-70 | | NRHS |
| 43 | ATTX | Trailer Train Co. (flat cars equipped with 2 continuous tie-down loops on centre sills, continuous tie-down rails on each side and bridge plates. Not equipped with hitches, chains, jacks, etc.) | 1/75-1/80 | | NRHS |
| 44 | ATTX | Trailer Train Co. | eliminated 1/92 | | NRHS |
| 45 | ATTX | TTX Co. | added 1/92 | | NRHS |
| 46 | ATTX | TTX Co. (flat cars equipped with 2 continuous tie-down loops on centre sills, continuous tie-down rails on each side. Not equipped with hitches, chains, jacks, etc.) | Jan-94 | | NRHS |
| 47 | ATTX | TTX Co. (60 ft. COFC flatcars, equipped with spark shields and container latches, capable of carrying 3-20 ft. containers, or 1-40 ft. and 1-20 ft. container, fully loaded to a maximum gross weight per car (containers and lading) of 159,000 lbs.) | Jul-00 | | NRHS |
| 48 | ATTX | *AMERICAN TURPENTINE & TAR CO. LTD. | | | PWRC |
| 49 | ATTX | +TTX COMPANY - TRAILER TRAIN CO. | | | PWRC |
| 50 | ATTX | American Turpentine & Tar (TTX Corporation) | | | RSRV |
| 51 | ATTX | TTX COMPANY | | | SCAC4 |
| 52 | ATTY | ARNETT TRUCKING COMPANY | | | SCAC3 |
| 53 | ATTY | ACTION TRANSPORT | | | SCAC4 |
