| 1 | II | IBC Airways, Inc. | ICAO: CSQ, Callsign: Chasqui, IATA Prefix: 175, formerly IBC Aviation Services Inc., d/b/a Western Air Freight | USA | AVCODES |
| 2 | II | Business Air Ltd. | ICAO: GNT, Callsign: Granite, Merged with British Midland Regional Limited on 05 February 2001. Established in 1987. Commenced operations in August 1987. | GB | AVCODES |
| 3 | II | Eurocity Express Ltd. | ICAO: LCY, Callsign: Stol, Renamed London city Airways Ltd. | GB | AVCODES |
| 4 | II | London City Airways Ltd. | ICAO: LCY, Callsign: Stol, Merged into British Midland. Formerly Eurocity Express Ltd. | GB | AVCODES |
| 5 | II | Airways (India) Ltd. | Callsign: Airways, Designator II recalled by IATA | IND | AVCODES |
| 6 | II | Evex Fluggsellschaft mbh & Co KG | Callsign: Sunbeam, | D | AVCODES |
| 7 | IIA | Interamericana de Aviacon Ltda. | Callsign: Interamericana, | CO | AVCODES |
| 8 | IIA | Inter Iles Air | IATA: I7, Callsign: Inter Iles, | COM | AVCODES |
| 9 | IIAF | Imperial Iranian Air Force | | IR | TRAFFIC |
| 10 | IIC | Inter Island Air Charter | Callsign: Inter Air, | BS | AVCODES |
| 11 | IICL | ITS INTERNATIONAL CONTAINER LINES I | | | SCAC4 |
| 12 | IICU | IWATANI CORPORATION | | J | BIC |
| 13 | IICU | IWATANI INTERNATIONAL CORPORATION | | | SCAC4 |
| 14 | IICX | Interlake Iron Corp. | 4/1938-4/1961; eliminated 7/1965 (reporting marks changed to ISCX) | | NAKINA |
| 15 | IICX | Interlake Iron Corp. (Toledo Furnace Plant) | 7/1932-7/1937 | | NAKINA |
| 16 | IICX | Interlake Iron Corp. (Toledo Furnace Plant) | Apr-38 | | NRHS |
| 17 | IICX | Interlake Iron Corp. | 1/52-4/61; eliminated 7/65 (reporting marks changed to ISCX) | | NRHS |
| 18 | IICX | INTERLAKE IRON CORP. (MERK CHANGED TO ISCX 7-95) | | | PWRC |
| 19 | IICZ | CANADIAN NATIONAL RWY [ILLINOIS CENTRAL GULF RAILROAD; ILLINOIS CENTRAL RR] | | | PWRC |
| 20 | IICZ | Illinois Central Railroad (Canadian National Railway) | | | RSRV |
| 21 | IIDP | INSTRUMENTOS INDUSTRIALES DEL PACIF | | | SCAC4 |
| 22 | IIDU | INTERMODAL INNOVATION LLP | | | SCAC4 |
| 23 | IIET | IET INTERNATIONAL ENERGY TECHNOLOGI | | | SCAC4 |
| 24 | IIG | International Company for Transport, Trade and Public Works | Callsign: Aldawlyh Air, | LAR | AVCODES |
| 25 | IIG | International Company for Transport, Trade and Pub | | | ICAO1 |
| 26 | IIIC | INNOVATIVE INTERMODAL INC | | | SCAC4 |
| 27 | IIID | INTRADE INDUSTRIES INC | | | SCAC4 |
| 28 | IIII | IRONWORKS INDUSTRIES INCORPORATED | | | SCAC4 |
| 29 | IIIN | IFYCO INVESTMENT INC | | | SCAC4 |
| 30 | IIIU | III TRANSPORTATION | | | PWRC |
| 31 | IIIU | III Transportation | | | RSRV |
| 32 | IIIZ | III TRANSPORTATION | | | PWRC |
| 33 | IIIZ | III Transportation | | | RSRV |
| 34 | IIIZ | IOWA INTERSTATE INTERMODAL | | | SCAC4 |
| 35 | IIL | India International Airways (P) Ltd. | Callsign: India Inter, | IND | AVCODES |
| 36 | IIL | India International Airways | | | ICAO1 |
| 37 | IILA | INTERTRANSPORT INTERNATIONAL | | | SCAC4 |
| 38 | IILL | IDEAL INSTALLATION LLC | | | SCAC4 |
| 39 | IILU | (IPCU) INDEPENDENT CONTAINER LINE | | | PWRC |
| 40 | IILU | Independent Container Line | | | RSRV |
| 41 | IILU | INDEPENDENT CONTAINER LINE LTD | | | SCAC1 |
| 42 | IILU | INDEPENDENT CONTAINER LINE | | | SCAC4 |
| 43 | IILZ | (IPCU) INDEPENDENT CONTAINER LINE | | | PWRC |
| 44 | IILZ | Independent Container Line | | | RSRV |
| 45 | IILZ | INDEPENDENT CONTAINER LINE | | | SCAC4 |
| 46 | IIMI | INTEGRITY IN MOTION INC | | | SCAC4 |
| 47 | IIMS | INDEPENDENCE INTERNATIONAL MOVING A | | | SCAC4 |
| 48 | IIN | Inter Island Airlines Lda | | CV | AVCODES |
| 49 | IIN | Inter Islands Airlines | IATA: H4, Designator H4 reinstated by IATA | CV | AVCODES |
| 50 | IIN | Inter Islands Airlines | IATA: H4 | | ICAO1 |
| 51 | IINA | ILLIANA TRANSPORTATION, INC | | | SCAC1 |
| 52 | IINA | ILLIANA TRANSPORTATION INC | | | SCAC4 |
| 53 | IIND | INTERSPED INC | | | SCAC4 |
| 54 | IINO | IINO LINES | | | SCAC4 |
| 55 | IINQ | INTER INC | | | SCAC4 |
| 56 | IIPI | INTER ISLAND PETROLEUM INC | | | SCAC4 |
| 57 | IIRC | Indiana Interstate Ry. Co., Inc. | added 4/1978; 1/1980; added 7/1980; eliminated 1/1983 | | NAKINA |
| 58 | IIRC | Indiana Interstate Ry. Co., Inc. | added 4/78; 1/80; added 7/80; eliminated 1/83 | | NRHS |
| 59 | IIRC | INDIANA INTERSTATE RAILWAY CO. | | | PWRC |
| 60 | IIRC | Indiana Interstate Railway | | | RSRV |
| 61 | IIRX | Independence Iowa Refrigerator Line | 7/1930-7/1935 | | NAKINA |
| 62 | IIRX | INDEPENDENCE IOWA REFRIGERATOR LINE | | | PWRC |
| 63 | IIRZ | III TRANSPORTATION | | | PWRC |
| 64 | IIRZ | III Transportation | | | RSRV |
| 65 | IIRZ | III TRANSPORTATION | | | SCAC4 |
| 66 | IISC | INTERNATIONAL INDUSTRIAL SUPPLIES | | | SCAC4 |
| 67 | IISU | INTERTRADE INTERNATIONAL SERVICES | | CH | BIC |
| 68 | IISX | I.I. Selig & Sons Ltd. | added 10/1968; 4/1970; eliminated 10/1970 | | NAKINA |
| 69 | IISX | I.I. Selig & Sons Ltd. | added 10/68; 4/70; eliminated 10/70 | | NRHS |
| 70 | IISX | I.I. SELIG & SONS LTD. | | | PWRC |
| 71 | IITN | INTERSTATE INTERMODAL TRANSPORT INC | | | SCAC4 |
| 72 | IITR | INTERNATIONAL TRANSPORT SERVCES LLC | | | SCAC4 |
| 73 | IIZ | ISSAQUAH INDUSTRY | | | PWRC |
