| 401 | ICDV | INTER-CITY DELIVERY | | | SCAC4 |
| 402 | ICDX | Inspiration Consolidated Copper Co. | 8/1920-7/1930 | | NAKINA |
| 403 | ICDX | INSPIRATION CONSOLIDATED COPPER CO | | | PWRC |
| 404 | ICE | Icelandair | IATA: FI, Callsign: Iceair, IATA Prefix: 108, | IS | AVCODES |
| 405 | ICE | Icelandair | IATA: FI | | ICAO1 |
| 406 | ICE | Iowa Chicago and Eastern R.R. Corp. | added 1/2003; 7/2005; eliminated 1/2010 | | NAKINA |
| 407 | ICE | IOWA, CHICAGO & EASTERN RAILROAD | | | PWRC |
| 408 | ICE | Iowa, Chicago and Eastern Railroad | | | RSRV |
| 409 | ICE | IOWA CHICAGO AND EASTERN RAILROAD C | | | SCAC4 |
| 410 | ICE | Icelandair | | IS | TRAFFIC |
| 411 | ICEA | ICECO ADVANCED ARENA PRODUCTS | | | SCAC4 |
| 412 | ICEB | ILLINOIS COLORADO EXPRESS INC | | | SCAC4 |
| 413 | ICED | ICECULTURE INC | | | SCAC4 |
| 414 | ICEE | INTERCONTINENTAL CARGO ENTERPRISES | | | SCAC4 |
| 415 | ICEG | I C E LOGISTICS INC | | | SCAC4 |
| 416 | ICEH | ICE PEARL NAVICATION CORP | | | SCAC4 |
| 417 | ICEI | Impresa di Construzioni Edili | Real: ICE | I | TRAFFIC |
| 418 | ICEJ | INDIAN CREEK EXPRESS LLC | | | SCAC4 |
| 419 | ICEK | INTERMODAL CARGO EXPRESS INC | | | SCAC4 |
| 420 | ICEM | INTERMODAL CARTAGE EXPRESS LLC | | | SCAC4 |
| 421 | ICEM | Italcementi | | I | TRAFFIC |
| 422 | ICEN | INTERSTATE COURIER EXPRESS INC | | | SCAC4 |
| 423 | ICEP | INTERNATIONAL CARGO EXPRESS CO LTD | | | SCAC4 |
| 424 | ICEQ | ICE EQUIPMENT INTERNATIONAL INC | | | SCAC4 |
| 425 | ICER | ICEPORT SHIPPING COMPANY LIMITED | | | SCAC4 |
| 426 | ICER | Iowa, Chicago & Eastern | Real: ICE | USA | TRAFFIC |
| 427 | ICES | INTER CITY EXPRESS | | | SCAC4 |
| 428 | ICET | ICE, ROBERT, TRUCK LINE, INC | | | SCAC1 |
| 429 | ICET | ICE TRANSPORT CO INC | | | SCAC4 |
| 430 | ICEU | INTER-CONTINENTAL EQUIPMENT, INC. | | | PWRC |
| 431 | ICEU | Inter-Continental Equipment | | | RSRV |
| 432 | ICEU | INTER-CONTINENTAL EQUIPMENT INC. | | | SCAC4 |
| 433 | ICEV | ISLAND CARGO EXPRESS | | | SCAC4 |
| 434 | ICEW | ICE WATER CO LTD | | | SCAC4 |
| 435 | ICEY | ICE TRANSPORTATION LLC | | | SCAC4 |
| 436 | ICEZ | GATX CAPITAL CORPORATION | | | PWRC |
| 437 | ICEZ | GATX Capital Corporation | | | RSRV |
| 438 | ICF | Inter-Cargo Service | Callsign: Intercargo, | UZ | AVCODES |
| 439 | ICF | ICS-Aero SM S.r.l. | Callsign: Incharter, | RSM | AVCODES |
| 440 | ICF | Interfrigo/Intercontainer | | BE | VKM |
| 441 | ICFA | IDEAITALIA CONTEMPORARY FURNITURE C | | | SCAC4 |
| 442 | ICFD | IRELAND, K & C FREIGHT LIMITED | | | SCAC4 |
| 443 | ICFI | IMPERIAL CFS INC | | | SCAC4 |
| 444 | ICFL | INLET CLIFFS LTD | | | SCAC4 |
| 445 | ICFS | INTERCOASTAL FREIGHT SERVICES INC | | | SCAC4 |
| 446 | ICFT | INTERNATIONAL CROSSING FREIGHT | | | SCAC4 |
| 447 | ICFU | ILYICHEVSK SHIP REPAIR YARD LLC | | | SCAC4 |
| 448 | ICG | Icelandic Coast Guard | Callsign: Iceland Coast, | IS | AVCODES |
| 449 | ICG | Icelandic Coast Guard | | | ICAO1 |
| 450 | ICG | Illinois Central R.R. Co. | added 4/1988; 1/1994-7/2005 | | NAKINA |
| 451 | ICG | Illinois Central Gulf R.R. Co. | 1/1975-1/1980; eliminated 4/1988 | | NAKINA |
| 452 | ICG | Illinois Central Gulf R.R. Co. | 1/75-1/80; eliminated 4/88 | | NRHS |
| 453 | ICG | Illinois Central R.R. Co. | added 4/88; 1/94-7/2000 | | NRHS |
| 454 | ICG | CANADIAN NATIONAL RWY [ILLINOIS CENTRAL GULF RAILROAD; ILLINOIS CENTRAL RR] | | | PWRC |
| 455 | ICG | Illinois Central Gulf Railroad (Canadian National Railway) | | | RSRV |
| 456 | ICG | Illinois Central Gulf | | USA | TRAFFIC |
| 457 | ICGB | INTERCARGO BROKERS LLC | | | SCAC4 |
| 458 | ICGC | INDY CARTAGE CO | | | SCAC1 |
| 459 | ICGI | INTELLECT CONTROLS GROUP INC | | | SCAC4 |
| 460 | ICGM | IMAGE CASTING MEXICO SA DE CV | | | SCAC4 |
| 461 | ICGN | INTERCARGA CONSOLIDADA SA DE CV | | | SCAC4 |
| 462 | ICGS | INTERMODAL CARTAGE EXPRESS INC | | | SCAC4 |
| 463 | ICGU | CANADIAN NATIONAL RWY [ILLINOIS CENTRAL GULF RAILROAD; ILLINOIS CENTRAL RR] | | | PWRC |
| 464 | ICGU | Illinois Central Gulf Railroad (Canadian National Railway) | | | RSRV |
| 465 | ICGZ | CANADIAN NATIONAL RWY [ILLINOIS CENTRAL GULF RAILROAD; ILLINOIS CENTRAL RR] | | | PWRC |
| 466 | ICGZ | Illinois Central Gulf Railroad (Canadian National Railway) | | | RSRV |
| 467 | ICGZ | ILLINOIS CENTRAL RAILROAD COMPANY | | | SCAC4 |
| 468 | ICH | Intercontinental Airways (Gambia) Limited | Callsign: Intercontinental, | WAG | AVCODES |
| 469 | ICHA | INTECHRA LOGISTICS LLC | | | SCAC4 |
| 470 | ICHC | ICHCO | | | SCAC4 |
| 471 | ICHE | INTERCHEM TRUCKING COMPANY | | | SCAC4 |
| 472 | ICHI | ISLAND CHARTER | | | SCAC4 |
| 473 | ICHI | Ichibata Electric Railway | | J | TRAFFIC |
| 474 | ICHL | INDUSTRIAL CHEMICAL CORP | | | SCAC4 |
| 475 | ICHR | ISLAND CITY HARBOR | | | SCAC4 |
| 476 | ICHU | INGETRA AG | | | PWRC |
| 477 | ICHU | Ingetra | | | RSRV |
| 478 | ICHU | CORINTH & COUNCE RAILROAD | | | SCAC3 |
| 479 | ICHU | EUROTAINER SAS | | | SCAC4 |
| 480 | ICI | Viking International Airlines (VIA) | Callsign: Iceman, | FIN | AVCODES |
| 481 | ICIA | ICI ARTIFICIAL LIFT INC | | | SCAC4 |
| 482 | ICIB | INTERNATIONAL CABINETS INC | | | SCAC4 |
| 483 | ICIE | INNERCITY EXPRESS INC | | | SCAC4 |
| 484 | ICIK | IMPACT CONTRACTORS INC | | | SCAC4 |
| 485 | ICIM | ICI MIDWEST LLC | | | SCAC4 |
| 486 | ICIM | ICIM ARAD SA | | RO | VKM |
| 487 | ICIMA | ICIM SA Arad | | RO | TRAFFIC |
| 488 | ICIN | INYO CRUDE INC | | | SCAC4 |
| 489 | ICIO | INTEGRAL CARRIERS INC | | | SCAC4 |
| 490 | ICIP | INSTANT COURIER INC | | | SCAC4 |
| 491 | ICIQ | I C E INC | | | SCAC4 |
| 492 | ICIT | INDUSTRIAS CITRICOLAS DE MONTEMOREL | | | SCAC4 |
| 493 | ICIU | INTERMODAL CONTAINERS INC | | | PWRC |
| 494 | ICIU | Intermodal Containers | | | RSRV |
| 495 | ICIX | ICI Americas Inc. | added 10/1979; 1/1980-1/1994; eliminated 4/1996; 7/2000-7/2005 (not listed) | | NAKINA |
| 496 | ICIX | ICI United States Inc. | added 10/1974; 1/1975; eliminated 10/1979 | | NAKINA |
| 497 | ICIX | ICI America Inc. | added 4/1972; eliminated 10/1974 | | NAKINA |
| 498 | ICIX | ICI America Inc. | added 4/72 | | NRHS |
| 499 | ICIX | ICI United States Inc. | Jan-75 | | NRHS |
| 500 | ICIX | ICI Americas Inc. | 1/80-1/94; eliminated 4/96; 7/2000 | | NRHS |
