| 1 | IC | Indian Airlines Corporation | ICAO: IAC, Callsign: Indair, IATA Prefix: 058, Name changed to NACIL d/b/a Indian Airlines. | IND | AVCODES |
| 2 | IC | NACIL d/b/a Indian Airlines | ICAO: IAC, Callsign: Indair, IATA Prefix: 058, Meregd into Air India. Name changed from Indian Airlines Corporation. | IND | AVCODES |
| 3 | IC | Illinois Central R.R. Co. | added 4/1988; 1/1994-7/2005 | | NAKINA |
| 4 | IC | Illinois Central Gulf R.R. Co. | eliminated 4/1988 | | NAKINA |
| 5 | IC | Illinois Central Gulf R.R. Co. (Illinois Central) | 1/1975-1/1980 | | NAKINA |
| 6 | IC | Illinois Central R.R. Co. | 4/1938-4/1970 | | NAKINA |
| 7 | IC | Illinois Central R.R. Co. (Illinois Central System) | 7/1930-7/1936 | | NAKINA |
| 8 | IC | Illinois Central R.R. Co. | 8/1920-7/1923 | | NAKINA |
| 9 | IC | Illinois Central R.R. Co. | 4/38-4/70 | | NRHS |
| 10 | IC | Illinois Central Gulf R.R. Co. (Illinois Central) | 1/75-1/80 | | NRHS |
| 11 | IC | Illinois Central Gulf R.R. Co. | eliminated 4/88 | | NRHS |
| 12 | IC | Illinois Central R.R. Co. | added 4/88; 1/94-7/2000 | | NRHS |
| 13 | IC | CANADIAN NATIONAL RWY [ILLINOIS CENTRAL GULF RAILROAD; ILLINOIS CENTRAL RR] | | | PWRC |
| 14 | IC | Illinois Central Railroad (Canadian National Railway) | | | RSRV |
| 15 | IC | ILLINOIS CENTRAL RAILROAD COMPANY | | | SCAC4 |
| 16 | IC | Illionis Central | | USA | TRAFFIC |
| 17 | ICA | Icaro | Callsign: Icarfly, | I | AVCODES |
| 18 | ICA | Intercoastal Airways, Inc. | Callsign: Intercoastal, | USA | AVCODES |
| 19 | ICA | Intercontinental Aero Leasing (Pty) Ltd | Callsign: Intercargo, | SD | AVCODES |
| 20 | ICA | Inversiones Tiryka C.A. | Callsign: Tiryka, | YV | AVCODES |
| 21 | ICA | Icaro | | | ICAO1 |
| 22 | ICAC | INTER-CAL CONTRACT CARRIERS | | | SCAC1 |
| 23 | ICAC | INTRA-CAL CONTRACT CARRIERS | | | SCAC4 |
| 24 | ICAL | INTERNATIONAL CARGO LOGISTICS | | | SCAC4 |
| 25 | ICAM | INSULATION CORPORATION OF | | | SCAC4 |
| 26 | ICAO | ICAT LOGISTICS INC | | | SCAC4 |
| 27 | ICAP | HOLIDAY ON ICE | | | PWRC |
| 28 | ICAQ | INTER CANADA A M EXPRESS INC | | | SCAC4 |
| 29 | ICAR | IMPORTACIONES Y EXPORTACIONES CALIF | | | SCAC4 |
| 30 | ICAT | INTER-CAL TRANSPORT | | | SCAC1 |
| 31 | ICAU | ICON INTERNATIONAL CONTAINER SERVICE (AMERICA) LLC | | USA | BIC |
| 32 | ICAU | Icon International Container Service | | | RSRV |
| 33 | ICAX | Inland Refining Co. | 8/1920-7/1923 | | NAKINA |
| 34 | ICAX | INLAND REFINING CO. | | | PWRC |
| 35 | ICB | Islandsflug HF | IATA: HH, Callsign: Icebird, IATA Prefix: 652, Designator HH recalled by IATA. Merged in Air Atlanta Icelandic. IATA designator changed from HT* | IS | AVCODES |
| 36 | ICB | Islandsflug HF | IATA: HT, Callsign: Icebird, IATA designator changed to HH | IS | AVCODES |
| 37 | ICB | Icebird Airline | | | ICAO1 |
| 38 | ICB | In der City Bus GmbH | City: Frankfurt am Main | D | TRAFFIC |
| 39 | ICBAF | Italian Co-Belligerent Air Force | Real: ACI, Aviazione Cobelligerante Italiana, 1943 - 1945 | I | TRAFFIC |
| 40 | ICBI | INTERNATIONAL COMPUTER BROKERS INC | | | SCAC4 |
| 41 | ICBL | Inter City Lines | | USA | TRAFFIC |
| 42 | ICBT | INTERSTATE FREIGHT SYSTEMS INC | | | SCAC4 |
| 43 | ICBU | INTERNATIONAL CONTAINER POOL PTE LTD | | SGP | BIC |
| 44 | ICBU | INTERNATIONAL CONTAINER POOL PTE LT | | | SCAC4 |
| 45 | ICBUS | IC Bus | | D | TRAFFIC |
| 46 | ICBV | ITIRO CORPORATION BVI | | | SCAC4 |
| 47 | ICC | Instituto Cartografico de Cataluna | Callsign: Carto, | E | AVCODES |
| 48 | ICC | Instituto Cartografico de Cataluna | | | ICAO1 |
| 49 | ICCB | INDUSTRIAL CHEMICALS CORPORATION | | | SCAC4 |
| 50 | ICCP | INTERGLOBAL CARGO CORP | | | SCAC4 |
| 51 | ICCU | ICCU CONTAINERS, INC. | | | PWRC |
| 52 | ICCU | ICCU Containers | | | RSRV |
| 53 | ICCX | International Catalyst Corp. | added 10/2001; 7/2005 | | NAKINA |
| 54 | ICCX | Inspiration Consolidated Copper Co. | added 7/1974; 1/1975; eliminated 10/1978 | | NAKINA |
| 55 | ICCX | Industrial Chemical Co. | 8/1920-7/1923 | | NAKINA |
| 56 | ICCX | Inspiration Consolidated Copper Co. | added 7/74; 1/75; eliminated 10/78 | | NRHS |
| 57 | ICCX | *INDUSTRIAL CHEMICAL CO. | | | PWRC |
| 58 | ICCX | *INSPIRATION CONSOLIDATED COPPER CO. | | | PWRC |
| 59 | ICCX | +INTERNATIONAL CATALYST CORP. | | | PWRC |
| 60 | ICCX | International Catalyst Corporation | | | RSRV |
| 61 | ICCX | INTERNATIONAL CATALYST CORPORATION | | | SCAC4 |
| 62 | ICCZ | INTERNATIONAL MINERAL CORP. | | | PWRC |
| 63 | ICD | Icaro S.A. | IATA: X8, Callsign: Icaro, IATA Prefix: 545, Founded in 1971. Ceased operations during 2011. | EC | AVCODES |
| 64 | ICD | Icaro | | | ICAO1 |
| 65 | ICDB | INDIAN CAPITAL DISTRIBUTION CO INC | | | SCAC4 |
| 66 | ICDF | INTERNATIONAL CRUISE DUTY FREE INC | | | SCAC4 |
| 67 | ICDL | INTER-CITY DELIVERY SERVICE, INC | | | SCAC1 |
| 68 | ICDL | INTER-CITY DELIVERY SERVICE INC | | | SCAC4 |
| 69 | ICDP | INTRA CITY DISPATCH INC | | | SCAC4 |
| 70 | ICDU | ICON INT. CONTAINER SERVICE GMBH | | D | BIC |
| 71 | ICDU | ICON INTERNATIONAL CONTAINER SERVIC | | | SCAC4 |
| 72 | ICDUE | I.C.E.F.E DUE SRL | | IT | VKM |
| 73 | ICDV | INTER CITY DELIVERY, INC | | | SCAC1 |
| 74 | ICDV | INTER-CITY DELIVERY | | | SCAC4 |
| 75 | ICDX | Inspiration Consolidated Copper Co. | 8/1920-7/1930 | | NAKINA |
| 76 | ICDX | INSPIRATION CONSOLIDATED COPPER CO | | | PWRC |
| 77 | ICE | Icelandair | IATA: FI, Callsign: Iceair, IATA Prefix: 108, | IS | AVCODES |
| 78 | ICE | Icelandair | IATA: FI | | ICAO1 |
| 79 | ICE | Iowa Chicago and Eastern R.R. Corp. | added 1/2003; 7/2005; eliminated 1/2010 | | NAKINA |
| 80 | ICE | IOWA, CHICAGO & EASTERN RAILROAD | | | PWRC |
| 81 | ICE | Iowa, Chicago and Eastern Railroad | | | RSRV |
| 82 | ICE | IOWA CHICAGO AND EASTERN RAILROAD C | | | SCAC4 |
| 83 | ICE | Icelandair | | IS | TRAFFIC |
| 84 | ICEA | ICECO ADVANCED ARENA PRODUCTS | | | SCAC4 |
| 85 | ICEB | ILLINOIS COLORADO EXPRESS INC | | | SCAC4 |
| 86 | ICED | ICECULTURE INC | | | SCAC4 |
| 87 | ICEE | INTERCONTINENTAL CARGO ENTERPRISES | | | SCAC4 |
| 88 | ICEG | I C E LOGISTICS INC | | | SCAC4 |
| 89 | ICEH | ICE PEARL NAVICATION CORP | | | SCAC4 |
| 90 | ICEI | Impresa di Construzioni Edili | Real: ICE | I | TRAFFIC |
| 91 | ICEJ | INDIAN CREEK EXPRESS LLC | | | SCAC4 |
| 92 | ICEK | INTERMODAL CARGO EXPRESS INC | | | SCAC4 |
| 93 | ICEM | INTERMODAL CARTAGE EXPRESS LLC | | | SCAC4 |
| 94 | ICEM | Italcementi | | I | TRAFFIC |
| 95 | ICEN | INTERSTATE COURIER EXPRESS INC | | | SCAC4 |
| 96 | ICEP | INTERNATIONAL CARGO EXPRESS CO LTD | | | SCAC4 |
| 97 | ICEQ | ICE EQUIPMENT INTERNATIONAL INC | | | SCAC4 |
| 98 | ICER | ICEPORT SHIPPING COMPANY LIMITED | | | SCAC4 |
| 99 | ICER | Iowa, Chicago & Eastern | Real: ICE | USA | TRAFFIC |
| 100 | ICES | INTER CITY EXPRESS | | | SCAC4 |
