Airline codes| IATA | ICAO | Airline | Call sign | Country | Comments |
|---|
| I4 | EXP | Island Air Express | ISLAND EXPRESS | United States | 2014 |
| IWL | Island Wings | | Bahamas | 2014 |
| IK | KAR | Ikar | IKAR | Russian Federation | |
| ICN | Iconair | | Pakistan | |
| IAC | Interaviation Charter | INTERCHARTER | Romania | |
| ITC | International Air Carrier Association | | Belgium | |
| IDG | IDG Technology Air | INDIGO | Czech Republic | |
| IFL | IFL Group | EIFEL | United States | |
| RDE | II Lione Alato Arl | FLIGHT RED | United Kingdom | |
| IJM | IJM International Jet Management | JET MANAGEMENT | Austria | |
| IKK | IKI International Airlines | IKIAIR | Japan | |
| IKN | IKON FTO | IKON | Germany | |
| BLU | IMP Aviation Services | BLUENOSE | Canada | |
| XGG | IMP Group Aviation Services | | Canada | |
| 1F | | INFINI Travel Information | | Japan | Computer Reservation System |
| IPA | IPEC Aviation | IPEC | Australia | |
| IPM | IPM Europe | SHIPEX | United Kingdom | |
| LVB | IRS Airlines | SILVERBIRD | Nigeria | |
| ISD | ISD Avia | ISDAVIA | Ukraine | |
| 1U | | ITA Software | | United States | Computer reservation system |
| FDF | IVV Femida | | Russia | |
| IB | IBE | Iberia Airlines | IBERIA | Spain | |
| II | CSQ | IBC Airways | CHASQUI | United States | |
| I2 | IBS | Iberia Express | IBEREXPRESS | Spain | Charter service, low cost carrier for EU flights of Iberia operating only A320s |
| IBR | Ibertour Servicios Aéreos | IBERTOUR | Spain | |
| IBT | Ibertrans Aérea | IBERTRANS | Spain | |
| TY | IWD | Iberworld | IBERWORLD | Spain | |
| FW | IBX | Ibex Airlines | IBEX | Japan | |
| IBC | Ibicenca Air | IBICENCA | Spain | |
| AKI | Ibk-Petra | | Sudan | |
| 0C | IBL | IBL Aviation | CATOVAIR | Mauritius | |
| BBL | IBM Euroflight Operations | BLUE | Switzerland | |
| YYY | ICAO | | | Used by airlines without a specific code |
| C3 | IPR | Independent Carrier (ICAR) | ICAR | Ukraine | |
| ICA | Icaro | ICARFLY | Italy | |
| ICD | Icaro Air | ICARO | Ecuador | Defunct 2011 |
| IUS | Icarus | ICARUS | Italy | |
| CIC | ICC Canada | AIR TRADER | Canada | |
| ICJ | Icejet | ICEJET | Iceland | |
| HC | | Iceland Express | | Iceland | defunct |
| FI | ICE | Icelandair | ICEAIR | Iceland | |
| ICG | Icelandic Coast Guard | ICELAND COAST | Iceland | |
| RAC | Icar Air | TUZLA AIR | Bosnia and Herzegovina | |
| FRC | Icare Franche Compte | FRANCHE COMPTE | France | |
| IFM | Ifly | ICOPTER | Greece | |
| IKR | Ikaros DK | IKAROS | Denmark | |
| CIO | Il Ciocco International Travel Service | CIOCCO | Italy | |
| ILV | Il-Avia | ILAVIA | Russia | |
| IDL | Ildefonso Redriguez | ILDEFONSO | Mexico | |
| V8 | IAR | Iliamna Air Taxi | ILIAMNA AIR | United States | |
| ILP | Ilpo Aruba Cargo | | Aruba | |
| ILL | Ilyich-Avia | ILYICHAVIA | Ukraine | |
| IMR | Imaer | IMAER | Portugal | |
| ITX | Imair Airlines | IMPROTEX | Azerbaijan | |
| PNX | Imperial Airways | PHOENIX | United States | ICAO code in use by another company, call sign no longer allocated |
| IMG | Imperial Cargo Airlines | IMPERIAL AIRLINES | Ghana | |
| IMT | Imtrec Aviation | IMTREC | Cambodia | |
| DH | IDE | Independence Air | INDEPENDENCE AIR | United States | defunct |
| IDP | Independent Air Freighters | INDEPENDENT | Australia | |
| I7 | IOA | IndiaOne Air | INDIA FIRST | India | |
| 6E | IGO | IndiGo | IFLY | India | InterGlobe Aviation |
| IIL | India International Airways | INDIA INTER | India | |
| IFC | Indian Air Force | INDIAN AIRFORCE | India | |
| IC | IAC | Indian Airlines | INDAIR | India | |
| IDR | Indicator Company | INDICATOR | Hungary | |
| I9 | IBU | Indigo Airlines | INDIGO BLUE | United States | |
| VP | AXC | Indochina Airlines | AIRSPUP | Vietnam | defunct |
| IDA | Indonesia Air Transport | INTRA | Indonesia | |
| QZ | AWQ | Indonesia AirAsia | WAGON AIR | Indonesia | |
| IO | IAA | Indonesian Airlines | INDO LINES | Indonesia | |
| IPN | Industri Pesawat Terbang Nusantara | NUSANTARA | Indonesia | |
| ITN | Industrias Titan | TITANLUX | Spain | |
| FFI | Infinit Air | INFINIT | Spain | |
| INS | Inflite The Jet Centre | | United Kingdom | |
| IVA | Innotech Aviation | INNOTECH | Canada | |
| INC | Insel Air International | INSELAIR | Netherlands Antilles | |
| ICC | Institut Cartogràfic de Catalunya | CARTO | Spain | |
| INT | Intair | INTAIRCO | Canada | |
| INL | Intal Avia | INTAL AVIA | Kyrgyzstan | |
| FFL | Intavia Limited | | United Kingdom | |
| XRA | Intensive Air | INTENSIVE | South Africa | |
| ITW | Inter Air | INTER WINGS | Bulgaria | |
| INX | Inter Express | INTER-EURO | Turkey | |
| IIC | Inter Island Air Charter | | Bahamas | 2014[1] |
| H4 | IIN | Inter Island Airways | | Cape Verde | |
| CAR | Inter RCA | QUEBEC ROMEO | Central African Republic | |
| NTT | Inter Tropic Airlines | INTER-TROPIC | Sierra Leone | |
| TCU | Inter Tropical Aviation | TROPAIR | Suriname | Defunct 2001 |
| ITA | Inter-Air | CAFEX | United States | |
| ICN | Inter-Canadian | INTER-CANADIAN | Canada | |
| UGL | Inter-Island Air | UGLY VAN | United States | |
| IMA | Inter-Mountain Airways | INTER-MOUNTAIN | United States | |
| ITS | Inter-State Aviation | INTER-STATE | United States | |
| D6 | ILN | Interair South Africa | INLINE | South Africa | |
| NTE | Interaire | INTERMEX | Mexico | |
| ZA | SUW | Interavia Airlines | ASTAIR | Russia | |
| IVT | Interaviatrans | INTERAVIA | Ukraine | |
| JY | IWY | InterCaribbean Airways | ISLANDWAYS | Turks and Caicos Islands | Name changed from Interisland Airways Limited and Air Turks & Caicos |
| RS | ICT | Intercontinental de Aviación | CONTAVIA | Colombia | |
| ICP | Intercopters | CHOPER | Spain | |
| IFT | Interflight | INTERFLIGHT | United Kingdom | |
| IJT | Interflight (Learjet) | | United Kingdom | |
| RFL | Interfly | INFLY | Italy | |
| IFF | Interfreight Forwarding | INTERFREIGHT | Sudan | |
| IGN | Interguide Air | DIVINE AIR | Nigeria | |
| ISN | Interisland Airlines | TRI-BIRD | Philippines | |
| IWY | Interisland Airways Limited | ISLANDWAYS | Turks and Caicos Islands | Name changed to Air Turks and Caicos |
| 4O | AIJ | Interjet | ABC AEROLINEAS | Mexico | |
| IHE | Interjet Helicopters | INTERCOPTER | Greece | |
| IJW | Interjet Inc. | JET WEST | United States | 2015[2] |
| ID | ITK | Interlink Airlines | INTERLINK | South Africa | |
| IAK | International Air Cargo Corporation | AIR CARGO EGYPT | Egypt | |
| EXX | International Air Corporation | EXPRESS INTERNATIONAL | United States | |
| N/A | NCC | NCC | T3 Aviation, Inc. | STARFLEET | United States | 2020[3] |
| IAX | International Air Services | INTERAIR SERVICES | Liberia | |
| 6I | IBZ | International Business Air | INTERBIZ | Sweden | was U5 |
| IBY | International Business Aircraft | CENTRAL STAGE | United States | |
| ICS | International Charter Services | INTERSERVI | Mexico | |
| ICX | International Charter Xpress | INTEX | United States | Defunct 1994 |
| RED | International Committee of the Red Cross | RED CROSS | Switzerland | |
| IIG | International Company for Transport, Trade and Public Works | ALDAWLYH AIR | Libya | |
| IFX | International Flight Training Academy | IFTA | United States | |
| IJA | International Jet Aviation Services | I-JET | United States | |
| HSP | International Jet Charter | HOSPITAL | United States | The Flying Hospital |
| THN | International Security Assistance Force | ATHENA | Canada | |
| RSQ | International SOS Windhoek | SKYMEDIC | Namibia | |
| ISF | International Stabilisation Assistance Force | | United Kingdom | |
| ITH | International Trans-Air | INTRANS NIGERIA | Nigeria | |
| IPT | Interport Corporation | INTERPORT | United States | |
| IKY | Intersky Bulgary | GENERAL SKY | Bulgaria | |
| 3L | ISK | Intersky | INTERSKY | Austria | Defunct |
| I4 | FWA | Interstate Airlines | FREEWAYAIR | Netherlands | Defunct |
| ITU | Intervuelos | INTERLOS | Mexico | |
| INV | Inversija | INVER | Latvia | |
| IND | Iona National Airways | IONA | Ireland | |
| IOA | Iowa Airways | IOWA AIR | United States | |
| IR | IRA | Iran Air | IRANAIR | Iran | Was B9 |
| EP | IRC | Iran Aseman Airlines | ASEMAN | Iran | |
| IRB | Iranair Tours | | Iran | |
| IRG | Iranian Naft Airlines | NAFT | Iran | |
| IA | IAW | Iraqi Airways | IRAQI | Iraq | |
| BIS | Irbis Air | IRBIS | Kazakhstan | |
| IRL | Irish Air Corps | IRISH | Ireland | |
| RDK | Irish Air Transport | IRISH TRANS | Ireland | |
| XMR | Irish Aviation Authority | AUTHORITY | Ireland | |
| IH | MZA | Irtysh Air | IRTYSH AIRLINES | Kazakhstan | Old IATA code: IT; old ICAO code: IRT |
| KCE | Irving Oil | KACEY | Canada | |
| ISI | Island Air | ISLANDMEX | Mexico | |
| ILF | Island Air Charters | ISLAND FLIGHT | United States | |
| XYZ | Island Air Express | RAINBIRD | United States | |
| ISA | Island Airlines | | United States | |
| SOY | Island Aviation | SORIANO | Philippines | |
| DQA | Island Aviation Services | | Maldives | |
| IOM | Island Aviation and Travel | ISLE AVIA | United Kingdom | |
| 2S | SDY | Island Express | SANDY ISLE | United States | |
| MTP | Island Helicopters | METROCOPTER | United States | |
| ILC | ILAS Air | | Japan | |
| IAJ | Islandair Jersey | JARLAND | United Kingdom | |
| CN | | Islands Nationair | | Papua New Guinea | |
| ICB | Icebird Airline | ICEBIRD | Iceland | |
| IF | ISW | Islas Airways | PINTADERA | Spain | |
| IGS | Isle Grande Flying School | ISLA GRANDE | United States | |
| WC | ISV | Islena De Inversiones | | Honduras | |
| IOS | Isles of Scilly Skybus | SCILLONIA | United Kingdom | |
| IAI | Israel Aircraft Industries | ISRAEL AIRCRAFT | Israel | |
| IAF | Israeli Air Force | | Israel | |
| 6H | ISR | Israir | ISRAIR | Israel | |
| IST | Istanbul Airlines | ISTANBUL | Turkey | |
| AZ | ITY | ITA Airways | ITARROW | Italy | |
| FS | ACL | Itali Airlines | SPADA | Italy | Former name: Transporti Aerei Italiani; former IATA Code: 9X*; former ICAO code: ACO |
| IAM | Italian Air Force | ITALIAN AIRFORCE | Italy | |
| IEI | Italian Army | ITALIAN ARMY | Italy | |
| GCI | Italian Coast Guard | ITALIAN COAST GUARD | Italy | |
| MMI | Italian Navy | ITALIAN NAVY | Italy | |
| IFS | Italy First | RIVIERA | Italy | |
| GI | IKA | Itek Air | ITEK-AIR | Kyrgyzstan | ?ICAO confirmed; IATA not |
| IVS | Ivoire Aero Services | IVOIRE AERO | Ivory Coast | |
| IVW | Ivoire Airways | IVOIRAIRWAYS | Ivory Coast | |
| IJE | Ivoire Jet Express | IVOIRE JET | Ivory Coast | |
| OIC | Iwamoto Crane Co Ltd | | Japan | |
| IXR | Ixair | X-BIRD | France | |
| H9 | IZM | Izair | IZMIR | Turkey | |
| IZA | Izhavia | IZHAVIA | Russia | |
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