| 1 | IG | Meridiana S.p.A. | ICAO: ISS, Callsign: Merair, IATA Prefix: 191, Merged with Eurofly S.p.A. | I | AVCODES |
| 2 | IG | Alisarda S.p.A. | ICAO: ISS, Callsign: Alisarda, IATA Prefix: 191, change of name to Meridiana S.p.A. | I | AVCODES |
| 3 | IG | Meridiana Fly S.p.A. | ICAO: EEZ, Callsign: Merair, IATA Prefix: 191, ICAO designator changed to ISS. Name changed to Meridiana Fly S.p.A. t/a Meridiana. Merged with Eurofly S.p.A. | I | AVCODES |
| 4 | IG | Meridiana Fly S.p.A. t/a Meridiana | ICAO: ISS, Callsign: Meridiana, IATA Prefix: 191, Name changed to Air Italy S.p.A. w.e.f. from 01 Amrch 2018.ICAO designator changed to ISS. Name changed to Meridiana Fly S.p.A. t/a Meridiana. ICAO callsign changed from Merair. Merged with Eurofly S.p.A. | I | AVCODES |
| 5 | IG | Air Italy S.p.A. | ICAO: ISS, Callsign: Air Italy, IATA Prefix: 191, Name changed from Meridiana Fly S.p.A. t/a Meridiana w.e.f. from 01 March 2018.ICAO designator changed to ISS. Name changed to Meridiana Fly S.p.A. t/a Meridiana. ICAO callsign changed from Merair. Merged with Eurofly S.p.A. | I | AVCODES |
| 6 | IG HSB | IG Harzer Schmalspurbahnen e.V. | Wernigerode | D | privat-bahn.de |
| 7 | IGA | SkyTaxi sp. z.o.o. | IATA: TE, Callsign: iguana, | PL | AVCODES |
| 8 | IGA | Skytaxi | | | ICAO1 |
| 9 | IGAB | Inlandsgods AB | 2001 - 2007 | S | svenska-lok.se |
| 10 | IGAB | Inlandsgods AB | 2001 - 2007 | S | TRAFFIC |
| 11 | IGAI | IGA INC | | | SCAC4 |
| 12 | IGAM | IN THE GAME INC. | | | SCAC4 |
| 13 | IGAS | INDUSTRIAL GAS DISTRIBUTORS | | | SCAC4 |
| 14 | IGAS | INTERGAS d.o.o. BEOGRAD | | RS | VKM |
| 15 | IGB | Industriebahngesellschaft Berlin mbH | Berlin | D | privat-bahn.de |
| 16 | IGB | Industriebahngesellschaft mbH (IGB) | | D | TRAFFIC |
| 17 | IGB | Industriebahn-Gesellschaft Berlin | | DE | VKM |
| 18 | IGBA | IGB AUTOMOTIVE LTD | | | SCAC4 |
| 19 | IGBL | INTERGLOBAL LOGISTICS INC | | | SCAC4 |
| 20 | IGBR | ITS GLOBAL RELOCATION SERVICES | | | SCAC4 |
| 21 | IGC | Iraq Gate | | IRQ | AVCODES |
| 22 | IGCM | INTERNATIONAL GLASS & CERAMICS | | | SCAC4 |
| 23 | IGCS | INDEPENDENT GLOBAL CARRIERS II LLC | | | SCAC4 |
| 24 | IGCU | INDEV SHIPPING SERVICES | | | SCAC4 |
| 25 | IGCX | INDUSTRIAL GENERATING CO. | | | PWRC |
| 26 | IGCZ | INDIANA GRAIN CO. | | | PWRC |
| 27 | IGE | Internationale Gesellschaft für Eisenbahnverkehr mbH | Hersbruck | D | privat-bahn.de |
| 28 | IGE | Internationale Gesellschaft für Eisenbahnverkehr | | D | TRAFFIC |
| 29 | IGE | IGE Bahntouristik | | DE | VKM |
| 30 | IGEBA | Ingenieurgesellschaft Bahn mbH | Krumbach | D | privat-bahn.de |
| 31 | IGEBA | IGeBa- Ingeniergesellschaft Bahn MbH | | DE | VKM |
| 32 | IGEU | ALPSANNA LIMITED | | IRL | BIC |
| 33 | IGEW | IGE \"Werrabahn Eisenach\" e.V | | DE | VKM |
| 34 | IGGU | AS INGLE | | | SCAC4 |
| 35 | IGHB | IG Hirzbergbahn e.V | | DE | VKM |
| 36 | IGHL | IGH LOGISTICS INC | | | SCAC4 |
| 37 | IGIC | IMPEX GLS INC | | | SCAC4 |
| 38 | IGIE | ICE GROUP INC, THE | | | SCAC4 |
| 39 | IGIH | IMPEX GROUP INC, THE | | | SCAC4 |
| 40 | IGIN | INTEGRATED INDUSTRIES INC | | | SCAC4 |
| 41 | IGIS | INCI GEMI ISLETME LTD STI | | | SCAC4 |
| 42 | IGL | Air Transport Iglesias S.A. | Callsign: Atisa, | YV | AVCODES |
| 43 | IGL | IGL sp. z o. o. | | PL | TRAFFIC |
| 44 | IGLI | INTEGRES GLOBAL LOGISTICS INC | | | SCAC4 |
| 45 | IGLO | INTELLIGENT LOGISTICS LLC | | | SCAC4 |
| 46 | IGLOO | Agro-industrial works Igloopol | City: Dębica | PL | TRAFFIC |
| 47 | IGLQ | INTERNATIONAL GROUND LOGISTICS LLC | | | SCAC4 |
| 48 | IGMI | INTERNATIONAL GLOBAL METALS INC | | | SCAC4 |
| 49 | IGMR | INGRAM READYMIX INC | | | SCAC4 |
| 50 | IGMT | INGRAM BROTHERS LLC | | | SCAC4 |
| 51 | IGN | Interguide Air Limited | Callsign: Divine Air, | WAN | AVCODES |
| 52 | IGN | Interguide Air | | | ICAO1 |
| 53 | IGN | International-Great Northern R.R. (Co). | 7/1930-7/1965 & 1/1975-1/1980 | | NAKINA |
| 54 | IGN | International-Great Northern R.R. | 4/38-7/65 & 1/75-1/80 | | NRHS |
| 55 | IGN | UP [MISSOURI PACIFIC] [INTERNATIONAL - GREAT NORTHERN RR] | | | PWRC |
| 56 | IGN | International-Great Northern | | | RSRV |
| 57 | IGN | International-Great Northern R.R. | | USA | TRAFFIC |
| 58 | IGN | IG Nebenbahn Nordhessen e.V | | DE | VKM |
| 59 | IGNI | IGNITION INC | | | SCAC4 |
| 60 | IGNJ | IMAGE ENGINEERING | | | SCAC4 |
| 61 | IGNS | IGNASH TRANSPORTING INCORPORATED | | | SCAC4 |
| 62 | IGNT | IGGYS TRANSPORTATION INC | | | SCAC4 |
| 63 | IGNU | GORO NICKEL S A S | | | SCAC4 |
| 64 | IGO | Interglobe Aviation Ltd. d/b/a Indigo | IATA: 6E, Callsign: Ifly, IATA Prefix: 312, | IND | AVCODES |
| 65 | IGO | IndiGo Airlines | IATA: 6E | | ICAO1 |
| 66 | IGO | IndiGo: InterGlobe Aviation Limited | | IND | TRAFFIC |
| 67 | IGOI | TRANSPORTES GOR | | | SCAC4 |
| 68 | IGOO | IGLOO TRANSPORT S DE RL DE CV | | | SCAC4 |
| 69 | IGOQ | I G L L | | | SCAC4 |
| 70 | IGOS | INDOCAN LOGISTICS INC | | | SCAC4 |
| 71 | IGOV | I-GO VAN & STORAGE CO | | | SCAC4 |
| 72 | IGOX | International Oil & Gas Corp. | 8/1920 | | NAKINA |
| 73 | IGOX | INTERNATIONAL OOL & GAS CORP. | | | PWRC |
| 74 | IGP | Igap | Callsign: Air Igap, | RUS | AVCODES |
| 75 | IGP | IG Preßnitztalbahn e.V. | Jöhstadt | D | privat-bahn.de |
| 76 | IGPN | INGLESIDE E N E | | | SCAC4 |
| 77 | IGPX | Industrial Steam Products | 7/2000-7/2005 (not listed) | | NAKINA |
| 78 | IGPX | Industrial Steam Products | Jul-00 | | NRHS |
| 79 | IGPX | INDUSTRIAL STEAM PRODUCTS | | | PWRC |
| 80 | IGPX | Industrial Steam Products | | | RSRV |
| 81 | IGPX | INDUSTRIAL STEAM PRODUCTS | | | SCAC4 |
| 82 | IGQU | L T I SRL / LOGISTICA TRASPORTI INT | | | SCAC4 |
| 83 | IGR | Iwate Galaxy Railway Company | | J | TRAFFIC |
| 84 | IGR | I.G.Rent, s.r.o. | | SK | VKM |
| 85 | IGRC | INTEGRITY RELOCATIONS INC | | | SCAC4 |
| 86 | IGRI | INTEGRITY INDUSTRIES | | | SCAC4 |
| 87 | IGRM | ILIES TRUCKING | | | SCAC4 |
| 88 | IGRY | INTEGRITY TRANSPORTATION SERVICES I | | | SCAC4 |
| 89 | IGS | Isle Grande Flying School | Callsign: Isla Grande, | USA | AVCODES |
| 90 | IGS | Isle Grande Flying School | | | ICAO1 |
| 91 | IGSC | INTEGRITY TRANSPORTATION SERVICES L | | | SCAC4 |
| 92 | IGSD | INTERGLOBAL SHIPPING 3001 LTD | | | SCAC4 |
| 93 | IGSE | IMPORTACIONES GELO SA DE CV | | | SCAC4 |
| 94 | IGSEE | IG 3seen Bahn e.V. | | DE | VKM |
| 95 | IGSL | INTEGRITY LOGISTICS LLC | | | SCAC4 |
| 96 | IGSR | INTEGRATED SERVICES INC | | | SCAC4 |
| 97 | IGSS | Interessengemeinschaft Schienebus Seelze e.V. | | DE | VKM |
| 98 | IGSU | CDN CONTAINER DEPOT NUERNBERG GMBH | | D | BIC |
| 99 | IGT | Georgian Airlines LLC d/b/a Aircompany Georgian Airlines | IATA: GH, Callsign: Sky Ika, IATA Prefix: 800, | GE | AVCODES |
| 100 | IGT | Industrieabnahmegesellschaft Transporttechnik mbH | Lengede | D | privat-bahn.de |
