| 1 | I | | | | TRAFFIC |
| 2 | I&GN | International-Great Northern R.R. Co. | 8/1920-7/1923 | | NAKINA |
| 3 | I&GN | INTERNATIONAL-GREAT NORTHERN RAILROAD CO. | | | PWRC |
| 4 | I&V | Iberia & Vermillion R.R. | 4/1938 | | NAKINA |
| 5 | I&V | Iberia & Vermillion R.R. (Southern Pacific Lines in Texas and Louisiana) | 8/1920-7/1936 | | NAKINA |
| 6 | I&V | Iberia & Vermillion R.R. | Apr-38 | | NRHS |
| 7 | I&V | IBERIA & VERMILLION RAILROAD 9SOUTHERN PACIFIC LINES IN TEXAS & LOUISIANA) | | | PWRC |
| 8 | I2 | Aeroturismo y Publicidad S.A.C. t/a Magenta Air | Commenced operations in September 2002. Ceased operations during 2005. | PE | AVCODES |
| 9 | I2 | Industrieflug IPS Air Service GmbH & Co. KG | | D | AVCODES |
| 10 | I2 | Compania Operadora de Corto y Medio Radio Iberia Express, S.A.U | ICAO: IBS, Callsign: Iberexpres, IATA Prefix: 060, | E | AVCODES |
| 11 | I3 | Cargo Three, Inc. | ICAO: CTW, Callsign: Third Cargo, IATA Prefix: 714, IATA Designator changed to 3J*. IATA Prefix code changed to 333. | PA | AVCODES |
| 12 | I3 | Ivoirenne de Transport Aerien | | CI | AVCODES |
| 13 | I3 | ATA Airlines | ICAO: TBZ, Callsign: Atalar Air, Established in 2009. Designator I3 recalled by IATA. | IR | AVCODES |
| 14 | I3 | innoAviation Limited | Non-airline Unit Load Devices (ULD) companies | HK | AVCODES |
| 15 | I4 | Interstate Airlines B.V. | ICAO: FWA, Callsign: Freewayair, Founded in 2005. Bankrupt in 2010. | NL | AVCODES |
| 16 | I4 | The Airline iFly | ICAO: RSY, Callsign: Russian Sky, IATA designator changed to F7. Designator H5 recalled by IATA | RUS | AVCODES |
| 17 | I4 | Scott Air, LLC d/b/a Island Air Express | | USA | AVCODES |
| 18 | I5 | Compagnie Aerienne du Mali S.A. (CAM) | ICAO: CMM, IATA Prefix: 261, Commenced operations on 07 June 2005. Name changed to Societe Nouvelle Air Mali w.e.f. 15 May 2009. Designator I5 reinstated by IATA | RMM | AVCODES |
| 19 | I5 | Societe Nouvelle Air Mali | ICAO: CMM, IATA Prefix: 261, Ceased operations on 27 December 2012. Name changed from Compagnie Aerienne du Mali S.A. w.e.f. 15 May 2009. Designator I5 reinstated by IATA | RMM | AVCODES |
| 20 | I5 | Air Asia (India) Private Limited t/a AirAsia India | ICAO: IAD, Callsign: Ariya, Founded on 28 March 2013. Commenced operations on 12 June 2014. Name changed to Air Asia (India) Ltd. ICAO callsign changed to Red Knight. | IND | AVCODES |
| 21 | I5 | Air Asia (India) Ltd. t/a AirAsia India | ICAO: IAD, Callsign: Red Knight, Founded on 28 March 2013. Commenced operations on 12 June 2014. Name changed from Air Asia (India) Private Limited. ICAO callsign changed from Ariya. | IND | AVCODES |
| 22 | I5 | AIX Connect Private Limited t/a AirAsia India | ICAO: IAD, Callsign: Red Knight, Founded on 28 March 2013. Commenced operations on 12 June 2014. Name changed from Air Asia (India) Private Limited. ICAO callsign changed from Ariya. | IND | AVCODES |
| 23 | I6 | Sky Eyes Co. Ltd. | ICAO: SEQ, Callsign: Sky eyes, | T | AVCODES |
| 24 | I6 | Mexicana Inter, S.A. de C.A. | ICAO: MXI, Ceased operations on 28 August 2010. | MEX | AVCODES |
| 25 | I6 | Air Indus (Pvt) Ltd | ICAO: MPK, Ceased operations on 01 July 2015. | PK | AVCODES |
| 26 | I6 | Intermodalidad de Levante S.A. | Railway Service | E | AVCODES |
| 27 | I7 | PT. Indonesia Air Transport. Tbk | ICAO: IDA, Callsign: Intra, Designator I7 recalled by IATA. | RI | AVCODES |
| 28 | I7 | Paramount Airways Pvt. Ltd. | ICAO: PMW, Callsign: Paraway, Founded in October 2005. AOC suspended as ceased operations in August 2010. | IND | AVCODES |
| 29 | I7 | Inter Iles Air | ICAO: IIA, Callsign: Inter Iles, | COM | AVCODES |
| 30 | I7 | GSEC Monarch and Deccan Aviation Private Limited d/b/a IndiaOne Air | ICAO: IOA, Callsign: India First, | IND | AVCODES |
| 31 | I8 | Izhavia Public Stock Company | ICAO: IZA, Callsign: Izhavia, | RUS | AVCODES |
| 32 | I8 | Aboriginal Air Services | Ceased operating on 17 September 2006. | AUS | AVCODES |
| 33 | I9 | Air-Serv, Inc d/b/a Indigo | ICAO: IBU, Callsign: Indigo Blue, Designator I9* recalled by IATA. Name changed from Indigo | USA | AVCODES |
| 34 | I9 | Indigo | Designator I9* recalled by IATA | USA | AVCODES |
| 35 | I9 | Indigo | Designator I9* reinstated by IATA. Name changed to Air-Serv, Inc d/b/a Indigo | USA | AVCODES |
| 36 | I9 | Air Italy S.p.A. | ICAO: AJR, Callsign: Air Italy, ICAO Designator changed to AEY. Designator NN recalled by IATA | I | AVCODES |
| 37 | I9 | Air Italy S.p.A. | ICAO: AEY, Callsign: Air Italy, ICAO Designator changed from AJR. Designator I9* recalled by IATA. Designator NN recalled by IATA | I | AVCODES |
| 38 | I9 | Air Italy S.p.A. | ICAO: AEY, Callsign: Air Italy, IATA Prefix: 067, Ceased operation on 11 February 2020. Name changed to Air Italy Fleet Management, S.p.A. w.e.f. 01 March 2018. AOC returned on 01 March 2018. ICAO Designator changed from AJR. Designator I9* reinstated by IATA. Designator NN recalled by IATA | I | AVCODES |
| 39 | I9 | Air Italy S.p.A. | ICAO: AEY, Callsign: Air Italy, Merged into Meridiana fly on 18 July 2011. IATA Accounting code and Prefix code recalled. ICAO Designator changed from AJR. Designator I9* reinstated by IATA. Designator NN recalled by IATA | I | AVCODES |
| 40 | I9 | Central Airlines Co., Ltd. | ICAO: HLF, Callsign: Homeland, IATA Prefix: 959, Name changed from Homeland Airlines Co., Ltd. Also known as Zhongzhou Airlines. | PRC | AVCODES |
| 41 | IA | Iraqi Airways | ICAO: IAW, Callsign: Iraqi, IATA Prefix: 073, Founded in 1945 | IRQ | AVCODES |
| 42 | IA | Iraqi Airways | Callsign: Iraqair, ICAO callsign changed to Iraqi | IRQ | AVCODES |
| 43 | IA | Macair Jet S.A. | ICAO: MCJ, Callsign: Jetmac, IATA Prefix: 177, IATA designator changed to A0. Designator VM recalled by IATA. | RA | AVCODES |
| 44 | IAA | PT Indonesian Airlines Av iapatria | IATA: IO, Callsign: Indo Lines, | RI | AVCODES |
| 45 | IAA | Inex Adria Aviopromet | IATA: JP, Callsign: Juliett Papa, | YU | AVCODES |
| 46 | IAA | Indonesian Airlines | IATA: IO | | ICAO1 |
| 47 | IAAU | INTERASIA LINES SINGAPORE PTE.LTD | | SGP | BIC |
| 48 | IAAU | INTERASIA LINES LTD | | | SCAC4 |
| 49 | IAAW | INTERNATIONAL PAPER-LAURENS CONTAIN | | | SCAC4 |
| 50 | IAB | Infinity Asia Co., Ltd | Callsign: Infinity Air, | T | AVCODES |
| 51 | IABA | INTER AMERICAN BUILDERS AGENCIES CO | | | SCAC4 |
| 52 | IAC | Indian Airlines Corporation | IATA: IC, Callsign: Indair, IATA Prefix: 058, Name changed to NACIL d/b/a Indian Airlines. | IND | AVCODES |
| 53 | IAC | NACIL d/b/a Indian Airlines | IATA: IC, Callsign: Indair, IATA Prefix: 058, Meregd into Air India. Name changed from Indian Airlines Corporation. | IND | AVCODES |
| 54 | IAC | Interaviation Charter | Callsign: Intercharter, | RO | AVCODES |
| 55 | IAC | Ibex Air Charter | Callsign: Ibex Airlines, | RL | AVCODES |
| 56 | IAC | Indian Airlines | IATA: IC | | ICAO1 |
| 57 | IACA | BIG ACE TRUCKING INC | | | SCAC4 |
| 58 | IACB | INTRADECO APPAREL INC | | | SCAC4 |
| 59 | IACG | INSEL AIR CARGO | | | SCAC4 |
| 60 | IACN | INTER ACTION COURIER INTERNATIONAL | | | SCAC4 |
| 61 | IACT | INTERNATIONAL ACTIVITIES CORPORATIO | | | SCAC4 |
| 62 | IACU | I.A.C.C. INTERNATIONAL ASSOCIATED | | ET | BIC |
| 63 | IACU | I A C C | | | SCAC4 |
| 64 | IACX | Canadian Industrial Alcohol Co., Ltd. | 7/1930-7/1932 | | NAKINA |
| 65 | IACX | CANADIAN INDUSTRIAL ALCOHOL CO., LTD. | | | PWRC |
| 66 | IAD | Airday Srl | IATA: 7S, Callsign: Airday, IATA designator changed to IM* | I | AVCODES |
| 67 | IAD | Airday Srl | IATA: IM, Callsign: Airday, Name changed to Fly Wez Srl. IATA designator changed from 7S | I | AVCODES |
| 68 | IAD | Fly Wex Srl | IATA: IM, Callsign: Flywex, Desigantor IM* recalled by IATA. Name changed from Airday Srl | I | AVCODES |
| 69 | IAD | Air Asia (India) Private Limited t/a AirAsia India | IATA: I5, Callsign: Ariya, Founded on 28 March 2013. Commenced operations on 12 June 2014. Name changed to Air Asia (India) Ltd. ICAO callsign changed to Red Knight. | IND | AVCODES |
| 70 | IAD | Air Asia (India) Ltd. t/a AirAsia India | IATA: I5, Callsign: Red Knight, Founded on 28 March 2013. Commenced operations on 12 June 2014. Name changed from Air Asia (India) Private Limited. ICAO callsign changed from Ariya. | IND | AVCODES |
| 71 | IAD | AIX Connect Private Limited t/a AirAsia India | IATA: I5, Callsign: Red Knight, Founded on 28 March 2013. Commenced operations on 12 June 2014. Name changed from Air Asia (India) Private Limited. ICAO callsign changed from Ariya. | IND | AVCODES |
| 72 | IAD | Fly Wex | | | ICAO1 |
| 73 | IAE | Interstate Airlines Limited | Callsign: Interstate, | WAN | AVCODES |
| 74 | IAE | AC Insat-Aero Ltd | | RUS | AVCODES |
| 75 | IAE | Closed Joint Stock Company IrAero | IATA: IO, Callsign: IrAero, | RUS | AVCODES |
| 76 | IAE | AC Insat-Aero | | | ICAO1 |
| 77 | IAEC | INFINITY AUTO EXPRESS INC | | | SCAC4 |
| 78 | IAED | IOWA EXPRESS FREIGHTWAYS, INC | | | SCAC1 |
| 79 | IAEI | I A E ENTERPRISES INC | | | SCAC4 |
| 80 | IAEP | INTER AMERICAN EXPRESS | | | SCAC4 |
| 81 | IAF | Israeli Air Force | | IL | AVCODES |
| 82 | IAF | Israeli Air Force | | | ICAO1 |
| 83 | IAF | Indian Air Force | | IND | TRAFFIC |
| 84 | IAFC | IMPORTED ARTISTS FILM COMPANY | | | SCAC4 |
| 85 | IAFE | | | YV | TRAFFIC |
| 86 | IAG | EPAG Groupe Air France | | | ICAO1 |
| 87 | IAGA | INAGUA LINES, INC. | | | SCAC1 |
| 88 | IAGA | INAGUA LINES INC | | | SCAC4 |
| 89 | IAGS | INTERMARE AGENCY SERVICES INC | | | SCAC4 |
| 90 | IAH | Island Airlines Hawaii | Callsign: Alakai, | USA | AVCODES |
| 91 | IAI | Israel Aircraft Industries Ltd. | Callsign: Israel Aircraft, Designator BK recalled by IATA | IL | AVCODES |
| 92 | IAI | Israel Aircraft Industries Ltd. | IATA: BK, Callsign: Bravo Kilo, Designator BK recalled by IATA. ICAO callsign changed to Israel Aircraft | IL | AVCODES |
| 93 | IAI | Israel Aircraft Industries | | | ICAO1 |
| 94 | IAIL | INNERSYSTEMS AUTOMOTIVE INC | | | SCAC4 |
| 95 | IAIN | IBC AIRWAYS INC | | | SCAC4 |
| 96 | IAIS | Iowa Interstate R.R., Ltd. | added 1/1985; 1/1994-7/2005 | | NAKINA |
| 97 | IAIS | Iowa Interstate R.R., Ltd. | added 1/85; 1/94-7/2000 | | NRHS |
| 98 | IAIS | IOWA INTERSTATE RAILROAD, LTD. | | | PWRC |
| 99 | IAIS | Iowa Interstate Railroad | | | RSRV |
| 100 | IAIS | Iowa Interstate | | USA | TRAFFIC |
