| 1 | IT | Irtysh Avia | ICAO: IRT, Callsign: Irtysh, Designator IT reinstated by IATA | KZ | AVCODES |
| 2 | IT | Air Inter | ICAO: ITF, Callsign: Air Inter, Founded on 12 November 1954. Commenced operations on 16 March 1958. Name changed to Air Inter Europe | F | AVCODES |
| 3 | IT | Irtysh-Avia | ICAO: IRT, Callsign: Irtysh, Designator IT recalled by IATA | KZ | AVCODES |
| 4 | IT | Air Inter Europe | ICAO: ITF, Callsign: Air Inter, Merged into Air France on 01 April 1997. | F | AVCODES |
| 5 | IT | Kingfisher Airlines Limited | ICAO: KFR, Callsign: Kingfisher, AOC temporarily suspended by Indian DGAC due financial issues. | IND | AVCODES |
| 6 | IT | Tiger Airways Taiwan Co. Ltd. | ICAO: TTW, Callsign: Smart Cat, IATA Prefix: 608, | RC | AVCODES |
| 7 | IT | IOWA TRANSFER RAILWAY CO. | | | PWRC |
| 8 | IT | INDIAN TRAILS INCORPORATED | | | SCAC4 |
| 9 | IT | Illinois Terminal | Real: ITC, City: Istanbul | USA | TRAFFIC |
| 10 | ITA | Inter-Air, Inc. | Callsign: Cafex, | USA | AVCODES |
| 11 | ITA | Inter-Air | | | ICAO1 |
| 12 | ITA | ILLINOIS MOTOR TRUCK OPERATORS ASSO | | | SCAC4 |
| 13 | ITAA | ITC MANAGEMENT B V | | | SCAC4 |
| 14 | ITAB | IRON BOX LOCAL TRUCKING | | | SCAC4 |
| 15 | ITAB | Interfleet AB | | SE | VKM |
| 16 | ITAD | IDAHO TRUCK SERVICE INC | | | SCAC4 |
| 17 | ITAE | ITL LAND TRANSPORTATION INC | | | SCAC4 |
| 18 | ITAG | IZA'S TRUCKING | | | SCAC4 |
| 19 | ITAG | Inlandståget AB | | SE | VKM |
| 20 | ITAL | I TALIA TRANSPORT SERVICE | | | SCAC4 |
| 21 | ITAM | INTER-AMERICAN MOVERS AND FORWARDER | | | SCAC4 |
| 22 | ITAO | ISLAND TRANSPORT LOGISTICS LLC | | | SCAC4 |
| 23 | ITAP | INDIGO TRANSPORTATION LLC | | | SCAC4 |
| 24 | ITAQ | INTEGRITY TRANSPORT LLC | | | SCAC4 |
| 25 | ITAS | INDEPENDENT TRANSPORTATION SERVICES | | | SCAC4 |
| 26 | ITAU | HAPAG LLOYD A.G | | D | BIC |
| 27 | ITAU | ITALIAN LINES | | | PWRC |
| 28 | ITAU | Italian Line | | | RSRV |
| 29 | ITAU | ITALIA DI NAVIGAZIONE | | | SCAC1 |
| 30 | ITAU | CP SHIPS | | | SCAC4 |
| 31 | ITAX | Illinois Transit Assembly Corp. | 7/2000-7/2005 (not listed) | | NAKINA |
| 32 | ITAX | Illinois Transit Assembly Corp. | Jul-00 | | NRHS |
| 33 | ITAX | ILLINOIS TRANSIT ASSEMBLY CORP. | | | PWRC |
| 34 | ITAX | Illinois Transit Assembly | | | RSRV |
| 35 | ITAX | ILLINOIS TRANSIT ASSEMBLY CORP | | | SCAC4 |
| 36 | ITB | Interbrasil Star, S.A. | IATA: Q9, Callsign: Interbrasil, IATA Prefix: 151, Designator Q9 recalled by IATA. Designator Q9 reinstated by IATA | BR | AVCODES |
| 37 | ITB | Island Tug & Barge | 1/1975-7/2005 | | NAKINA |
| 38 | ITB | Island Tug & Barge | 1/75-7/2000 | | NRHS |
| 39 | ITB | Industrietransportgesellschaft Brandenburg GmbH | Brandenburg (Villmann-Gruppe) | D | privat-bahn.de |
| 40 | ITB | ISLAND TUG & BARGE | | | PWRC |
| 41 | ITB | Island Tug and Barge | | | RSRV |
| 42 | ITB | ITB Transportgesellschaft mbH | | D | TRAFFIC |
| 43 | ITB | Industrietransportgesellschaft Brandenburg | | DE | VKM |
| 44 | ITBB | IRVIN TRUCKING INC | | | SCAC4 |
| 45 | ITBC | INTERCONTINENTAL TRUCK BROKERAGE CO | | | SCAC4 |
| 46 | ITBD | ISHAN TRANSPORT INC | | | SCAC4 |
| 47 | ITBE | IEDEMA TRUCKING | | | SCAC4 |
| 48 | ITBL | ITB CANAD LTD | | | SCAC4 |
| 49 | ITBU | INTERMODAL TRADING AGENCIES BV | | | SCAC4 |
| 50 | ITC | International Air Carrier Association (IACA) | | B | AVCODES |
| 51 | ITC | International Air Carrier Association | | | ICAO1 |
| 52 | ITC | Norfolk Southern Ry. Co. (Norfolk Southern) | added 1/1991; 1/1994-7/2005 | | NAKINA |
| 53 | ITC | Norfolk and Western Ry. Co. | added 7/1982; eliminated 1/1991 | | NAKINA |
| 54 | ITC | Illinois Terminal R.R. Co. | 1/1941-10/1966 & 1/1975-1/1980; eliminated 4/1982 | | NAKINA |
| 55 | ITC | Illinois Terminal R.R. Co. | 1/52-10/66 & 1/75-1/80; eliminated 4/82 | | NRHS |
| 56 | ITC | Norfolk and Western Ry. Co. | added 7/82; eliminated 1/91 | | NRHS |
| 57 | ITC | Norfolk Southern Ry. Co. | added 1/91; 1/94-7/2000 | | NRHS |
| 58 | ITC | NORFOLK SOUTHERN RAILWAY [ILLINOIS TERMINAL RR; NORFOLK & WESTERN RAILROAD] | | | PWRC |
| 59 | ITC | Illinois Terminal Railroad (Norfolk Southern) | | | RSRV |
| 60 | ITC | ILLINOIS TERMINAL RAILROAD COMPANY | | | SCAC4 |
| 61 | ITC | | City: Contanta | RO | TRAFFIC |
| 62 | ITCA | INSPECTECH ANALYGAS GROUP INC | | | SCAC4 |
| 63 | ITCD | INTERCITY DIRECT | | | SCAC4 |
| 64 | ITCF | INDEPENDENCE TRUCKING CORPORATION | | | SCAC4 |
| 65 | ITCG | INLAND TRAFFIC CONTROL INC | | | SCAC4 |
| 66 | ITCH | INTERNATIONAL TOUCH CONSOLIDATOR IN | | | SCAC4 |
| 67 | ITCK | INTERNATIONAL PAPER (HOUSTON CONTAI | | | SCAC4 |
| 68 | ITCL | INTERNACIONAL DE ELEVADORES SA DE C | | | SCAC4 |
| 69 | ITCM | INTERTRANS CARRIER COMPANY | | | SCAC4 |
| 70 | ITCN | IT CORPORATION | | | SCAC1 |
| 71 | ITCO | Island Terminal Company | | USA | TRAFFIC |
| 72 | ITCOKE | Italiana Coke | | I | TRAFFIC |
| 73 | ITCQ | IVRAJ TRANSPORT LTD | | | SCAC4 |
| 74 | ITCT | INTEGRA ADHESIVES INC | | | SCAC4 |
| 75 | ITCU | INTERCONTAINER S.A. | | E | BIC |
| 76 | ITCU | INTERCONTAINER | | | PWRC |
| 77 | ITCU | Intercontainer | | | RSRV |
| 78 | ITCV | ITC INTERNATIONAL | | | SCAC4 |
| 79 | ITCW | INFONET TECHNOLOGY CORPORATION | | | SCAC4 |
| 80 | ITCX | International Technologies Corp. | 7/2000-7/2005 (not listed) | | NAKINA |
| 81 | ITCX | Interstate Transport Co. | 7/1935-4/1961; eliminated 10/1963 | | NAKINA |
| 82 | ITCX | Interstate Transport Co. | 4/38-4/61 | | NRHS |
| 83 | ITCX | International Technologies Corp. | Jul-00 | | NRHS |
| 84 | ITCX | *INTERSTATE TRANSPORT CO. | | | PWRC |
| 85 | ITCX | +INTERNATIONAL TECHNOLOGIES CORPORATION | | | PWRC |
| 86 | ITCX | International Technologies Corporation | | | RSRV |
| 87 | ITCY | ILIAMNA TRANSPORTATION COMPANY LLC | | | SCAC4 |
| 88 | ITCZ | INTERCONTINENTAL TERMINALS COMPANY | | | PWRC |
| 89 | ITD | Inter Trans Avia | IATA: Y5, Callsign: Seitek, | KS | AVCODES |
| 90 | ITDM | ICONS TRADING COMPANY | | | SCAC4 |
| 91 | ITDP | INTERNATIONAL TRUCK DRIVERS COOPERA | | | SCAC4 |
| 92 | ITDS | INTERMODAL TRANSPORTATION & DISTRIB | | | SCAC4 |
| 93 | ITDU | INTERMODALTRASPORTI SRL | | I | BIC |
| 94 | ITDX | SULCOM, Inc. | added 10/1997; 7/2000-7/2005 | | NAKINA |
| 95 | ITDX | SULCOM, Inc. | added 10/97; 7/2000 | | NRHS |
| 96 | ITDX | SULCOM INCORPORATED | | | PWRC |
| 97 | ITDX | SULCOM | | | RSRV |
| 98 | ITDX | SULCOM INC | | | SCAC4 |
| 99 | ITE | Interestatal de Aviacion, S.A. de C.V. | Callsign: Interstatal, | MEX | AVCODES |
| 100 | ITE | Aerotaxi S.r.o. | Callsign: Aerotaxi, | CZ | AVCODES |
