| 1 | ICR | Eagle Aero, Inc. | Callsign: Icarus Flights, | USA | AVCODES |
| 2 | ICR | ICARO Service | Callsign: Icaro, | RCH | AVCODES |
| 3 | ICR | Eagle Aero | | | ICAO1 |
| 4 | ICRC | I C R LOGISTICS LLC | | | SCAC4 |
| 5 | ICRK | Indian Creek R.R. Co. | added 1/1984; eliminated 1/1990; 1/1994-7/2005 | | NAKINA |
| 6 | ICRK | Indian Creek R.R. Co. | eliminated 1/90; 1/94-7/2000 | | NRHS |
| 7 | ICRK | Island Creek Coal Co. | added 1/79; 1/80; eliminated 7/89 | | NRHS |
| 8 | ICRK | Island Creek Corp. | added 7/89; 1/94-7/2000 | | NRHS |
| 9 | ICRK | INDIAN CREEK RAILROAD CO. | | | PWRC |
| 10 | ICRK | Indian Creek Railroad | | | RSRV |
| 11 | ICRL | INTERCON CARRIERS LC | | | SCAC4 |
| 12 | ICRO | INTER-CROSS | | | SCAC4 |
| 13 | ICRP | INTERTRANS CORPORATION | | | SCAC4 |
| 14 | ICRS | INTERMODAL CARGO SERVICES INC | | | SCAC4 |
| 15 | ICRU | RESOURCE OVERSEAS GENERAL TRADING L.L.C. | | UAE | BIC |
| 16 | ICRU | *(ICHU) RETIRED 10-22-92 ATP | | | PWRC |
| 17 | ICRU | *INGETRA AG | | | PWRC |
| 18 | ICRU | Ingetra | | | RSRV |
| 19 | ICRV | IMPERIAL CARRIER SERVICES, LLC | | | SCAC4 |
| 20 | ICRX | Island Creek Corp. | added 7/1989; 1/1994-7/2005 (not listed) | | NAKINA |
| 21 | ICRX | Island Creek Coal Co. | added 1/1979; 1/1980; eliminated 7/1989 | | NAKINA |
| 22 | ICRX | *IRON CLIFFS RAILWAY COMPANY | | | PWRC |
| 23 | ICRX | +ISLAND CREEK CORPORATION {ISLAND CREEK COAL COMPANY] | | | PWRC |
| 24 | ICRX | Island Creek Coal | | | RSRV |
| 25 | ICRZ | CANADIAN NATIONAL RWY [ILLINOIS CENTRAL GULF RAILROAD] [ILLINOIS CENTRAL RR] | | | PWRC |
| 26 | ICRZ | Illinois Central Railroad (Canadian National Railway) | | | RSRV |
| 27 | ICRZ | ILLINOIS CENTRAL RAILROAD COMPANY | | | SCAC4 |
