| Airline Name | ICAO | IATA | Callsign | Country |
| IAC - Integrated Aviation Consortium | United Kingdom | |||
| Iberia | IBE | IB | IBERIA | Spain |
| Iberworld | IWD | TY | IBERWORLD | Spain |
| Ibex Airlines | Japan | |||
| Icaro Air | X8 | Ecuador | ||
| ICC Canada Ltd | CIC | Canada | ||
| Icejet | ICJ | ICEJET | Iceland | |
| Iceland Express | FHE | HW | FLY HELLO | Iceland |
| Icelandair | ICE | FI | ICEAIR | Iceland |
| ICS - Inter Ciel Service | ICS | France | ||
| Impulse Airlines | IPU | VQ | Australia | |
| Independence Air | IDE | DH | INDEPENDENCE | United States |
| Indian Airlines | IAC | IC | INDAIR | India |
| Indigo | IBU | I9 | United States | |
| IndiGo | IGO | 6E | IFLY | India |
| Indonesia Air Transport | IDA | Indonesia | ||
| Indonesia AirAsia | AWQ | QZ | WAGON AIR | Indonesia |
| Indonesian Air Force | Indonesia | |||
| Indonesian Airlines | IAA | IO | Indonesia | |
| Indus Air | India | |||
| Inex-Adria Airways | ADR | JP | Yugoslavia | |
| Inner Mongolian Airlines | China | |||
| Insel Air | INC | 7I | INSEL AIR | Netherlands Antilles |
| Intair | INT | ND | Canada | |
| Intair Link | Serbia And Montenegro | |||
| Intal Air | INL | Kyrgyzstan | ||
| Intel Leasing Corporation | United States | |||
| Inter (Intercontinental de Aviacion) | ICT | RS | INTER | Colombia |
| Inter Air | D6 | South Africa | ||
| Inter Air Services | Algeria | |||
| Inter Airlines | INX | 6K | INTER-EURO | Turkey |
| Inter Cargo Service | ICS | France | ||
| Inter European Airways | IEA | IP | United Kingdom | |
| Inter-Canadian (Canadian Regional) | ICN | ND | INTERCANADIAN | Canada |
| Inter-Canadien | ICN | ND | Canada | |
| Interflug | IFL | IF | INTERFLUG | German Democratic Republic |
| InterJet | INJ | INJET | Greece | |
| Interjet | AIJ | 4O | INTERJET | Mexico |
| Interlink Airlines | ITK | ID | South Africa | |
| Intermediacion Aerea Compania Aerea | IEA | Spain | ||
| International Caribbean Airways | Barbados | |||
| Interot Airways | IRT | IQ | Germany | |
| Intersky | ISK | 3L | Austria | |
| Interstate Equipment Leasing | United States | |||
| Ion Tiriac Air | Romania | |||
| Iran Air | IRA | IR | Iran, Islamic Republic Of | |
| Iran Air Force | Iran, Islamic Republic Of | |||
| Iran Air Tours | IRB | B9 | Iran, Islamic Republic Of | |
| Iran Aseman Airlines | IRC | EP | Iran, Islamic Republic Of | |
| Iraqi Airways | IAW | IA | Iraq | |
| Iraqi Government | Iraq | |||
| Ireland Airways (EI Air Exports) | EIX | 2E | AIR EXPORTS | Ireland |
| IRS Airlines | LVB | Nigeria | ||
| ISD Avia | ISD | Ukraine | ||
| Ishtar Airlines | Unknown | |||
| Isla Airlines | Unknown | |||
| Island Air | MKU | United States | ||
| Island Aviation Services | Q2 | Maldives | ||
| Islandsflug | ICB | HH | ICEBIRD | Iceland |
| Islas Airways | ISW | IF | PINTADERA | Spain |
| Islena Airlines | ISV | WC | Honduras | |
| Islena de Aviacion | ILA | Colombia | ||
| Israel Aircraft Industries | IAI | Israel | ||
| Israir Airlines | ISR | 6H | Israel | |
| Istanbul Airlines | IST | IL | Turkey | |
| Italair | DRG | B8 | Italy | |
| ItAli Airlines | ACL | 9X | Italy | |
| Italy First | IFS | IF | Italy | |
| Itek Air | IKA | GI | ITEK AIR | Kyrgyzstan |
| ITT Flight Operations | United States | |||
| Izmir Airlines | IHY | H9 | IZMIR | Turkey |