| 2001 | IN | Ryan Aviation Corp. d/b/a Ryan International Airlines | ICAO: RYN, Callsign: Ryan International, Desigantor IN rcalled by IATA | USA | AVCODES |
| 2002 | IN | JSC Aircompany Invest Avia | ICAO: TLG, Callsign: Talgat, Ceased operations. | KZ | AVCODES |
| 2003 | IN | PT. Nam Air | ICAO: LKN, Callsign: Namair, Subsidiary of Sriwijaya Air | RI | AVCODES |
| 2004 | IN | Indiana Northeastern R.R. Co. | added 7/1993; 1/1994-7/2005 | | NAKINA |
| 2005 | IN | Indiana Northwestern R.R. Co. | added 4/1993; eliminated 7/1993 | | NAKINA |
| 2006 | IN | Illinois Northern R.R. Co. | 1/1950-10/1966 & 1/1975; eliminated 4/1975 | | NAKINA |
| 2007 | IN | Illinois Northern Ry. | 4/1947 | | NAKINA |
| 2008 | IN | Illinois Northern R.R. Co. | 4/1938-1/1946 | | NAKINA |
| 2009 | IN | Illinois Northern Ry. | 7/1923-7/1936 | | NAKINA |
| 2010 | IN | Illinois Northern R.R. Co. | 4/38-10/66 & 1/75; eliminated 4/75 | | NRHS |
| 2011 | IN | Indiana Northwestern R.R. Co. | added 4/93; eliminated 7/93 | | NRHS |
| 2012 | IN | Indiana Northeastern R.R. Co. | added 7/93; 1/94-7/2000 | | NRHS |
| 2013 | IN | *ILLINOIS NORTHERN RAILROAD | | | PWRC |
| 2014 | IN | +INDIANA NORTHEASTERN RAILROAD CO. [INDIANA NORTHWESTERN RAILROAD CO.] | | | PWRC |
| 2015 | IN | Indiana Northeastern Railroad | | | RSRV |
| 2016 | IN | INDIANA NORTHEASTERN RAILROAD COMPA | | | SCAC4 |
| 2017 | IN | Illinois Northern R.R. Co. | | USA | TRAFFIC |
| 2018 | INA | Aero Internacional, S.A. de C.V. | Callsign: Aero-nacional, | MEX | AVCODES |
| 2019 | INA | Interair (Aviation) Ltd. | Callsign: Griffon, | GB | AVCODES |
| 2020 | INA | Indiana Airways, Inc. | Callsign: Indi-Air, | USA | AVCODES |
| 2021 | INA | Aero International | | | ICAO1 |
| 2022 | INA | Indian Army | | IND | TRAFFIC |
| 2023 | INA | INA d.d. | | HR | VKM |
| 2024 | INAB | INSTALACIONES INABENSA | | ES | VKM |
| 2025 | INAC | INTERNATIONAL TRADE ALLIANCE INC | | | SCAC4 |
| 2026 | INAE | INTERIORES AEREOS S A DE C V | | | SCAC4 |
| 2027 | INAF | INSTANT AIR FREIGHT COMPANY | | | SCAC4 |
| 2028 | INAG | INSTANT AGAIN LLC | | | SCAC4 |
| 2029 | INAK | INA TRUCKING | | | SCAC4 |
| 2030 | INAO | INFINITY LOGISTICS MANAGEMENT | | | SCAC4 |
| 2031 | INAP | INAPART INC. | | | SCAC4 |
| 2032 | INAR | INTERNATIONAL DELIVERY S DE RL DE C | | | SCAC4 |
| 2033 | INAS | INLAND PLASTICS LTD | | | SCAC4 |
| 2034 | INAT | INTERNAUT SHIPPING GMBH | | | SCAC4 |
| 2035 | INAU | NASHVILLE & ASHLAND CITY RAILROAD | | | SCAC3 |
| 2036 | INAY | INLAND NORTH AMERICA | | | SCAC4 |
| 2037 | INAZ | INTALCO ALUMINUM | | | PWRC |
| 2038 | INB | Instalbud | | PL | AVCODES |
| 2039 | INB | Inter Build LLC | Callsign: Interbuild, | TJ | AVCODES |
| 2040 | INBK | INTEGRITY LLAMA FARM | | | SCAC4 |
| 2041 | INBR | INTERNATIONAL BORDER SUPPLY | | | SCAC4 |
| 2042 | INBU | SEACUBE CONTAINERS LLC | | USA | BIC |
| 2043 | INBU | Seacube Container Leasing | | | RSRV |
| 2044 | INBU | SEACASTLE CONTAINER LEASING LLC | | | SCAC4 |
| 2045 | INBUG | INTERBUG Sp. z o.o. | | PL | VKM |
| 2046 | INC | Jet Air Internacional Charters, C.A. | Callsign: Interchart, | YV | AVCODES |
| 2047 | INC | Insel Air International N.V. | IATA: 7I, Callsign: Insel Air, IATA Prefix: 958, Ceased operations on 16 February 2019. | NA | AVCODES |
| 2048 | INC | Insel Air International | | | ICAO1 |
| 2049 | INC | COMMER | | | SCAC4 |
| 2050 | INCA | INTER-COASTAL INC | | | SCAC4 |
| 2051 | INCB | INDEPENDENT TRANSFER SERVICES INC | | | SCAC4 |
| 2052 | INCC | INSPIRATION CONSOLIDATED COPPER CO. | | | PWRC |
| 2053 | INCE | INCE DENIZCILIK VE TIC A S | | | SCAC4 |
| 2054 | INCF | INTERSTATE CONTAINER | | | SCAC4 |
| 2055 | INCH | INTERCHANGE COMPANY INC | | | SCAC4 |
| 2056 | INCJ | INTERCHANGE GROUP INC | | | SCAC4 |
| 2057 | INCK | INKEL, ADRIEN TRUCKING INC | | | SCAC4 |
| 2058 | INCN | INTERCONNECT INC | | | SCAC4 |
| 2059 | INCO | INSTANT COURIER | | | SCAC4 |
| 2060 | INCQ | INCHCAPE SHIPPING SERVICES | | | SCAC4 |
| 2061 | INCT | INTERNATIONAL CARRIERS (TILBURY) IN | | | SCAC4 |
| 2062 | INCU | INNOVACION CONTENEDOR PTE LTD | | SGP | BIC |
| 2063 | INCU | INTERCONTINENTAL TRANSPORT B.V. (ICT) | | | PWRC |
| 2064 | INCU | Intercontinental Transport | | | RSRV |
| 2065 | INCU | INTERCONTINENTAL TRANSPOR0 (ICT) BV | | | SCAC4 |
| 2066 | INCV | INTERSTATE CARTAGE COMPANY INC | | | SCAC4 |
| 2067 | INCW | INTERCITY LINES INC | | | SCAC4 |
| 2068 | INCX | Inco Ltd. | added 4/1990; 1/1994-7/2005; eliminated 10/2005 | | NAKINA |
| 2069 | INCX | Inco Ltd. | added 4/90; 1/94-7/2000 | | NRHS |
| 2070 | INCX | INCO LIMITED | | | PWRC |
| 2071 | INCX | Inco Railway | | | RSRV |
| 2072 | INCX | VALE INCO LIMITED | | | SCAC4 |
| 2073 | INCX | Inco Ltd. | | USA | TRAFFIC |
| 2074 | INCY | INTERNATIONAL FREIGHT SERVICES | | | SCAC4 |
| 2075 | INCZ | INTERCONTINENTAL TRANSPORT B.V. (ICT) | | | PWRC |
| 2076 | INCZ | Intercontinental Transport | | | RSRV |
| 2077 | INCZ | Intercontinental Transport | | | RSRV |
| 2078 | INCZ | INTERCONTINENTAL TRANSPORT B.V. (IC | | | SCAC4 |
| 2079 | IND | Iona National Airways Limited | Callsign: Iona, Ceased operations on 14 December 1994. | IRL | AVCODES |
| 2080 | IND | S Group International | Founded in 2013. Ceased operations. | KS | AVCODES |
| 2081 | IND | Iona National Airways | | | ICAO1 |
| 2082 | INDA | INDEL-DAVIS INC | | | SCAC4 |
| 2083 | INDC | INDUSTRIAL CHEMICALS DIV. A. C. CORP. | | | PWRC |
| 2084 | INDC | INDEPENDENT TRANSFER | | | SCAC4 |
| 2085 | INDE | INDEPENDENT TRANSPORTATION INC | | | SCAC4 |
| 2086 | INDF | INTER UNITED FREIGHTWAYS | | | SCAC4 |
| 2087 | INDG | INDEPENDENT DIRT & DOZIER INC | | | SCAC4 |
| 2088 | INDH | INDIANHEAD TRUCK LINE, INC. | | | SCAC1 |
| 2089 | INDH | INDUSTRIAS SL SA DE CV | | | SCAC4 |
| 2090 | INDI | INDIANA INTERSTATE | | | PWRC |
| 2091 | INDI | INDUSTRIES LAPLANTE INC | | | SCAC4 |
| 2092 | INDJ | INDEPENDENT TRANSPORT LLC | | | SCAC4 |
| 2093 | INDK | INDUSTRIAS DURO SA DE CV | | | SCAC4 |
| 2094 | INDL | INDUSTRIAL TRANSPORT INC | | | SCAC4 |
| 2095 | INDM | INDUSTRIAS NEM DE MEXICO SA DE CV | | | SCAC4 |
| 2096 | INDP | INLAND TRANSPORT INTERNATIONAL INC | | | SCAC4 |
| 2097 | INDR | Industry railway | General prefix for for small industrial railways, factory shunters | X | TRAFFIC |
| 2098 | INDS | INDUSTRIAL SERVICE CORP | | | SCAC4 |
| 2099 | INDU | INDOX ENERGY SYSTEMS SL | | E | BIC |
| 2100 | INDU | DOROTHEA MARINE ENTREPRISE AND MANAGEMENT | | | PWRC |
