| 1 | IN | Makedonski Aviotransport-Macedonian Airlines | ICAO: MAK, Callsign: Makavio, IATA Prefix: 367, Ceased operations on 01 September 2009 after AOC revoked. Established on 16 January 1994. Commenced operations on 23 June 1994. | MK | AVCODES |
| 2 | IN | Aerlinte Eireann | Callsign: Shamrock, | IRL | AVCODES |
| 3 | IN | Ryan Aviation Corp. d/b/a Ryan International Airlines | ICAO: RYN, Callsign: Ryan International, Desigantor IN rcalled by IATA | USA | AVCODES |
| 4 | IN | JSC Aircompany Invest Avia | ICAO: TLG, Callsign: Talgat, Ceased operations. | KZ | AVCODES |
| 5 | IN | PT. Nam Air | ICAO: LKN, Callsign: Namair, Subsidiary of Sriwijaya Air | RI | AVCODES |
| 6 | IN | Indiana Northeastern R.R. Co. | added 7/1993; 1/1994-7/2005 | | NAKINA |
| 7 | IN | Indiana Northwestern R.R. Co. | added 4/1993; eliminated 7/1993 | | NAKINA |
| 8 | IN | Illinois Northern R.R. Co. | 1/1950-10/1966 & 1/1975; eliminated 4/1975 | | NAKINA |
| 9 | IN | Illinois Northern Ry. | 4/1947 | | NAKINA |
| 10 | IN | Illinois Northern R.R. Co. | 4/1938-1/1946 | | NAKINA |
| 11 | IN | Illinois Northern Ry. | 7/1923-7/1936 | | NAKINA |
| 12 | IN | Illinois Northern R.R. Co. | 4/38-10/66 & 1/75; eliminated 4/75 | | NRHS |
| 13 | IN | Indiana Northwestern R.R. Co. | added 4/93; eliminated 7/93 | | NRHS |
| 14 | IN | Indiana Northeastern R.R. Co. | added 7/93; 1/94-7/2000 | | NRHS |
| 15 | IN | *ILLINOIS NORTHERN RAILROAD | | | PWRC |
| 16 | IN | +INDIANA NORTHEASTERN RAILROAD CO. [INDIANA NORTHWESTERN RAILROAD CO.] | | | PWRC |
| 17 | IN | Indiana Northeastern Railroad | | | RSRV |
| 18 | IN | INDIANA NORTHEASTERN RAILROAD COMPA | | | SCAC4 |
| 19 | IN | Illinois Northern R.R. Co. | | USA | TRAFFIC |
| 20 | INA | Aero Internacional, S.A. de C.V. | Callsign: Aero-nacional, | MEX | AVCODES |
| 21 | INA | Interair (Aviation) Ltd. | Callsign: Griffon, | GB | AVCODES |
| 22 | INA | Indiana Airways, Inc. | Callsign: Indi-Air, | USA | AVCODES |
| 23 | INA | Aero International | | | ICAO1 |
| 24 | INA | Indian Army | | IND | TRAFFIC |
| 25 | INA | INA d.d. | | HR | VKM |
| 26 | INAB | INSTALACIONES INABENSA | | ES | VKM |
| 27 | INAC | INTERNATIONAL TRADE ALLIANCE INC | | | SCAC4 |
| 28 | INAE | INTERIORES AEREOS S A DE C V | | | SCAC4 |
| 29 | INAF | INSTANT AIR FREIGHT COMPANY | | | SCAC4 |
| 30 | INAG | INSTANT AGAIN LLC | | | SCAC4 |
| 31 | INAK | INA TRUCKING | | | SCAC4 |
| 32 | INAO | INFINITY LOGISTICS MANAGEMENT | | | SCAC4 |
| 33 | INAP | INAPART INC. | | | SCAC4 |
| 34 | INAR | INTERNATIONAL DELIVERY S DE RL DE C | | | SCAC4 |
| 35 | INAS | INLAND PLASTICS LTD | | | SCAC4 |
| 36 | INAT | INTERNAUT SHIPPING GMBH | | | SCAC4 |
| 37 | INAU | NASHVILLE & ASHLAND CITY RAILROAD | | | SCAC3 |
| 38 | INAY | INLAND NORTH AMERICA | | | SCAC4 |
| 39 | INAZ | INTALCO ALUMINUM | | | PWRC |
| 40 | INB | Instalbud | | PL | AVCODES |
| 41 | INB | Inter Build LLC | Callsign: Interbuild, | TJ | AVCODES |
| 42 | INBK | INTEGRITY LLAMA FARM | | | SCAC4 |
| 43 | INBR | INTERNATIONAL BORDER SUPPLY | | | SCAC4 |
| 44 | INBU | SEACUBE CONTAINERS LLC | | USA | BIC |
| 45 | INBU | Seacube Container Leasing | | | RSRV |
| 46 | INBU | SEACASTLE CONTAINER LEASING LLC | | | SCAC4 |
| 47 | INBUG | INTERBUG Sp. z o.o. | | PL | VKM |
| 48 | INC | Jet Air Internacional Charters, C.A. | Callsign: Interchart, | YV | AVCODES |
| 49 | INC | Insel Air International N.V. | IATA: 7I, Callsign: Insel Air, IATA Prefix: 958, Ceased operations on 16 February 2019. | NA | AVCODES |
| 50 | INC | Insel Air International | | | ICAO1 |
| 51 | INC | COMMER | | | SCAC4 |
| 52 | INCA | INTER-COASTAL INC | | | SCAC4 |
| 53 | INCB | INDEPENDENT TRANSFER SERVICES INC | | | SCAC4 |
| 54 | INCC | INSPIRATION CONSOLIDATED COPPER CO. | | | PWRC |
| 55 | INCE | INCE DENIZCILIK VE TIC A S | | | SCAC4 |
| 56 | INCF | INTERSTATE CONTAINER | | | SCAC4 |
| 57 | INCH | INTERCHANGE COMPANY INC | | | SCAC4 |
| 58 | INCJ | INTERCHANGE GROUP INC | | | SCAC4 |
| 59 | INCK | INKEL, ADRIEN TRUCKING INC | | | SCAC4 |
| 60 | INCN | INTERCONNECT INC | | | SCAC4 |
| 61 | INCO | INSTANT COURIER | | | SCAC4 |
| 62 | INCQ | INCHCAPE SHIPPING SERVICES | | | SCAC4 |
| 63 | INCT | INTERNATIONAL CARRIERS (TILBURY) IN | | | SCAC4 |
| 64 | INCU | INNOVACION CONTENEDOR PTE LTD | | SGP | BIC |
| 65 | INCU | INTERCONTINENTAL TRANSPORT B.V. (ICT) | | | PWRC |
| 66 | INCU | Intercontinental Transport | | | RSRV |
| 67 | INCU | INTERCONTINENTAL TRANSPOR0 (ICT) BV | | | SCAC4 |
| 68 | INCV | INTERSTATE CARTAGE COMPANY INC | | | SCAC4 |
| 69 | INCW | INTERCITY LINES INC | | | SCAC4 |
| 70 | INCX | Inco Ltd. | added 4/1990; 1/1994-7/2005; eliminated 10/2005 | | NAKINA |
| 71 | INCX | Inco Ltd. | added 4/90; 1/94-7/2000 | | NRHS |
| 72 | INCX | INCO LIMITED | | | PWRC |
| 73 | INCX | Inco Railway | | | RSRV |
| 74 | INCX | VALE INCO LIMITED | | | SCAC4 |
| 75 | INCX | Inco Ltd. | | USA | TRAFFIC |
| 76 | INCY | INTERNATIONAL FREIGHT SERVICES | | | SCAC4 |
| 77 | INCZ | INTERCONTINENTAL TRANSPORT B.V. (ICT) | | | PWRC |
| 78 | INCZ | Intercontinental Transport | | | RSRV |
| 79 | INCZ | Intercontinental Transport | | | RSRV |
| 80 | INCZ | INTERCONTINENTAL TRANSPORT B.V. (IC | | | SCAC4 |
| 81 | IND | Iona National Airways Limited | Callsign: Iona, Ceased operations on 14 December 1994. | IRL | AVCODES |
| 82 | IND | S Group International | Founded in 2013. Ceased operations. | KS | AVCODES |
| 83 | IND | Iona National Airways | | | ICAO1 |
| 84 | INDA | INDEL-DAVIS INC | | | SCAC4 |
| 85 | INDC | INDUSTRIAL CHEMICALS DIV. A. C. CORP. | | | PWRC |
| 86 | INDC | INDEPENDENT TRANSFER | | | SCAC4 |
| 87 | INDE | INDEPENDENT TRANSPORTATION INC | | | SCAC4 |
| 88 | INDF | INTER UNITED FREIGHTWAYS | | | SCAC4 |
| 89 | INDG | INDEPENDENT DIRT & DOZIER INC | | | SCAC4 |
| 90 | INDH | INDIANHEAD TRUCK LINE, INC. | | | SCAC1 |
| 91 | INDH | INDUSTRIAS SL SA DE CV | | | SCAC4 |
| 92 | INDI | INDIANA INTERSTATE | | | PWRC |
| 93 | INDI | INDUSTRIES LAPLANTE INC | | | SCAC4 |
| 94 | INDJ | INDEPENDENT TRANSPORT LLC | | | SCAC4 |
| 95 | INDK | INDUSTRIAS DURO SA DE CV | | | SCAC4 |
| 96 | INDL | INDUSTRIAL TRANSPORT INC | | | SCAC4 |
| 97 | INDM | INDUSTRIAS NEM DE MEXICO SA DE CV | | | SCAC4 |
| 98 | INDP | INLAND TRANSPORT INTERNATIONAL INC | | | SCAC4 |
| 99 | INDR | Industry railway | General prefix for for small industrial railways, factory shunters | X | TRAFFIC |
| 100 | INDS | INDUSTRIAL SERVICE CORP | | | SCAC4 |
