| 1 | ITT | Inter Trans Air | Callsign: Inter Transair, | B | AVCODES |
| 2 | ITTB | I T TRANSPORT INC | | | SCAC4 |
| 3 | ITTC | ITT CARTAGE INC | | | SCAC4 |
| 4 | ITTG | IMPRINT TECHNOLOGIES INC | | | SCAC4 |
| 5 | ITTI | INTERNATIONAL TRANSPORT CARRIER | | | SCAC4 |
| 6 | ITTN | INTER-LINE TRANSPORT INC | | | SCAC4 |
| 7 | ITTO | ITT ONTARIO PRO SERVICE | | | SCAC4 |
| 8 | ITTR | ITT RAYONIER RAILROAD | | | PWRC |
| 9 | ITTR | ITT Rayonier Railroad | | USA | TRAFFIC |
| 10 | ITTS | INTEGRATED TRANSPORTATION SERVICES | | | SCAC4 |
| 11 | ITTT | INTERNATIONAL TRANSPORTATION SERVIC | | | SCAC4 |
| 12 | ITTU | INTERMODAL TANK TRANSPORT INC. | | USA | BIC |
| 13 | ITTV | INTERSTATE TOWING & TRANSPORT SERVI | | | SCAC4 |
| 14 | ITTX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 15 | ITTX | Trailer Train Co. | added 7/1965; 7/1965-1/1980; eliminated 1/1992 | | NAKINA |
| 16 | ITTX | Trailer Train Co. (FC flats specifically equipped to carry trucks (saddle back)) | added 7/1965; 7/1965 | | NAKINA |
| 17 | ITTX | Trailer Train Co. (FMS flats specifically equipped to carry trucks (saddle back)) | 10/1966-10/1968 | | NAKINA |
| 18 | ITTX | Trailer Train Co. (flat cars equipped with end pedestals and 62 tie-down winches with chains and bridge plates for transporting trailer tractors saddleback style) | 4/1970-7/1985 | | NAKINA |
| 19 | ITTX | Trailer Train Co./TTX Co. (flat cars equipped with 32 tie-down winches with chains, may be equipped with pedestals, for transporting trailer tractors, large trucks and military vehicles) | 10/1991-1/1994 | | NAKINA |
| 20 | ITTX | TTX Co. (flat cars equipped with 32 tie-down winches with chains, may be equipped with pedestals, for transporting trailer tractors, large trucks and military vehicles, equipped with end of car cush.) | 7/2000 | | NAKINA |
| 21 | ITTX | Trailer Train Co. (FMS flats specifically equipped to carry trucks (saddle back)) | added 7/65; 7/65-10/68 | | NRHS |
| 22 | ITTX | Trailer Train Co. | Apr-70 | | NRHS |
| 23 | ITTX | Trailer Train Co. (flat cars equipped with end pedestals and 62 tie-down winches with chains and bridge plates for transporting trailer tractors saddleback style) | 1/75-1/80 | | NRHS |
| 24 | ITTX | Trailer Train Co. | eliminated 1/92 | | NRHS |
| 25 | ITTX | TTX Co. | added 1/92 | | NRHS |
| 26 | ITTX | TTX Co. (flat cars equipped with 32 tie-down winches with chains, may be equipped with pedestals, for transporting trailer tractors, large trucks and military vehicles) | Jan-94 | | NRHS |
| 27 | ITTX | TTX Co. (flat cars equipped with 32 tie-down winches with chains, may be equipped with pedestals, for transporting trailer tractors, large trucks and military vehicles, equipped with end of car cush.) | Jul-00 | | NRHS |
| 28 | ITTX | TTX COMPANY-TRAILER TRAIN | | | PWRC |
| 29 | ITTX | Trailer Train (TTX Corporation) | | | RSRV |
| 30 | ITTX | TTX COMPANY | | | SCAC4 |
| 31 | ITTZ | ITT GRINNEL | | | PWRC |
