| 1 | IZ | Arkia Israeli Airlines Ltd. | ICAO: AIZ, Callsign: Arkia, IATA Prefix: 238, Name changed from Arkia Israel Inland Airlines | IL | AVCODES |
| 2 | IZ | Arkia Israel Inland Airlines | ICAO: AIZ, Callsign: Arkia, IATA Prefix: 238, Name changed to Arkia Israeli Airlines Ltd. | IL | AVCODES |
| 3 | IZA | Izhavia Public Stock Company | IATA: I8, Callsign: Izhavia, | RUS | AVCODES |
| 4 | IZA | Izhavia | | | ICAO1 |
| 5 | IZCX | Indiana Wood Preserving Co. | 7/1923 | | NAKINA |
| 6 | IZCX | Indiana Zinc Creosoting Co. | 8/1920 | | NAKINA |
| 7 | IZCX | *INDIANA ZINC CREOSOTING CO. | | | PWRC |
| 8 | IZCX | *INDIANA WOOD PRESERVING CO. | | | PWRC |
| 9 | IZG | Zagros Airlines | IATA: ZV, Callsign: Zagros, IATA Designator ZV recalled. Founded in 2005. | IR | AVCODES |
| 10 | IZG | Zagros Airlines | Callsign: Zagros, IATA Designator ZV recalled. Founded in 2005. | IR | AVCODES |
| 11 | IZG | Zagros Airlines | | | ICAO1 |
| 12 | IZICH | Izumo Ichibata Kotsu | | J | TRAFFIC |
| 13 | IZM | IHY Izmir Havayollari A.S. t/a iZair | IATA: 4I, IATA Prefix: 597, Founded in April 2005. Merged into Pegasus Airlines by end 2018. | TR | AVCODES |
| 14 | IZM | Izair | IATA: H9 | | ICAO1 |
| 15 | IZOU | IZOTOP ST PETERSBURG JSC | | RUS | BIC |
| 16 | IZOU | IZOTOP ENTERPRISE | | | SCAC4 |
| 17 | IZX | Illinois Zinc Co. | 8/1920-7/1923; 7/1935; 7/1937 (not listed) | | NAKINA |
| 18 | IZX | ILLINOIS ZINC CO. | | | PWRC |
| 19 | IZZO | IZZOS OIL SERVICE | | | SCAC4 |
