| 1 | IH | Falcon Air AB | ICAO: FCN, Callsign: Falcon, IATA Prefix: 759, Founded in 1986. Ceased operations during 2006. Designator IH recalled by IATA | S | AVCODES |
| 2 | IH | Lynden Air Cargo LLC | IATA designator changed to L2 | USA | AVCODES |
| 3 | IH | Algesa, Aerolineas Guinea Ecuatorial | ICAO: IHA, Callsign: Algesa, | GQ | AVCODES |
| 4 | IH | JSC Aircompany Irtysh-Air | ICAO: MZA, | KZ | AVCODES |
| 5 | IH | Southern Sky Airlines | ICAO: SRS, Callsign: Sky South, Subsidary of SCAT Airlines. | KZ | AVCODES |
| 6 | IH | UK International Airlines Limited | Formed on 13 September 2005. Commenced operations on 19 October 2007. Suspended all operations since 27 December 2007. | GB | AVCODES |
| 7 | IHA | Algesa, Aerolineas Guinea Ecuatorial | IATA: IH, Callsign: Algesa, | GQ | AVCODES |
| 8 | IHAN | IRON HANDCRAFTERS | | | SCAC4 |
| 9 | IHAS | IDEAL HARNESS | | | SCAC4 |
| 10 | IHAU | IHORA CHEMICAL INDUSTRIAL | | | PWRC |
| 11 | IHAU | Ihora Chemical Industrial | | | RSRV |
| 12 | IHB | Indiana Harbor Belt R.R. Co. | 1/1975-7/2005 | | NAKINA |
| 13 | IHB | Indiana Harbor Belt R.R. Co. | 1/75-7/2000 | | NRHS |
| 14 | IHB | INDIANA HARBOR BELT RAILROAD CO. | | | PWRC |
| 15 | IHB | Indiana Harbor Belt Railroad | | | RSRV |
| 16 | IHB | Indiana Harbor Belt | | USA | TRAFFIC |
| 17 | IHC | Iran Helicopter Company | Callsign: Heliran, | IR | AVCODES |
| 18 | IHC | International Harvester | | USA | TRAFFIC |
| 19 | IHCA | INVESTORS HOLDING CO LTD | | | SCAC4 |
| 20 | IHCI | INTERNATIONAL HAZMAT CROSSINGS INC | | | SCAC4 |
| 21 | IHCS | ICE HAWK CORPORATION SA | | | SCAC4 |
| 22 | IHCT | IHC TRANSPORTATION | | | SCAC1 |
| 23 | IHCU | UNASSIGNED | | | PWRC |
| 24 | IHCX | International Harvester Co. | 1/1941-7/1965; eliminated 10/1965 | | NAKINA |
| 25 | IHCX | International Harvester Co. | 1/52-7/65; eliminated 10/65 | | NRHS |
| 26 | IHCX | INTERNATIONAL HARVESTER CO. | | | PWRC |
| 27 | IHCX | International Harvester Co. | | USA | TRAFFIC |
| 28 | IHDS | IN HOUSE DELIVERY SYS INC | | | SCAC4 |
| 29 | IHE | Interjet Helicopters | Callsign: Intercopter, | GR | AVCODES |
| 30 | IHE | Interjet Helicopters | | | ICAO1 |
| 31 | IHEC | INDUSTRIES P H L INC | | | SCAC4 |
| 32 | IHEP | IRON HORSE EXPRESS LLC | | | SCAC4 |
| 33 | IHES | IRON HORSE ENERGY SERVICES | | | SCAC4 |
| 34 | IHFI | ICON HEALTH & FITNESS INC | | | SCAC4 |
| 35 | IHHC | INLACH & COLLINS BROTHERS LLC | | | SCAC4 |
| 36 | IHHL | INTEGRITY HEAVY HAUL LLC | | | SCAC4 |
| 37 | IHHS | INTERIDE HEAVY HAUL LC | | | SCAC4 |
| 38 | IHHU | INFRABUILD | | AUS | BIC |
| 39 | IHIL | INDIAN HILLS PRODUCE INC | | | SCAC4 |
| 40 | IHINV | IH Invest s.r.o. | | SK | VKM |
| 41 | IHKC | IRONHORSE TRUCKING CO | | | SCAC4 |
| 42 | IHLA | INTERFREIGHT HARMONIZED LOGISTICS I | | | SCAC4 |
| 43 | IHLN | IMPRIMERIE HLN INC | | | SCAC4 |
| 44 | IHLU | ITERA HOLDING LTD | | | SCAC4 |
| 45 | IHLW | INDOCHINA LIMITED | | | SCAC4 |
| 46 | IHMZ | INDIAN HEAD MINING CO. | | | PWRC |
| 47 | IHO | Seven Four Eight Air Services (K) Limited | IATA: H4, Callsign: Sefeas, IATA Prefix: 874, IATA designator changed to FE. | EAK | AVCODES |
| 48 | IHO | Seven Four Eight Air Services (K) Limited | IATA: FE, Callsign: Sefeas, IATA Prefix: 874, IATA designator changed from H4* | EAK | AVCODES |
| 49 | IHO | 748 Air Services | | EAK | TRAFFIC |
| 50 | IHOD | INGRAM HOLDINGS | | | SCAC4 |
| 51 | IHOU | INTERMODAL TANK TRANSPORT INC. | | USA | BIC |
| 52 | IHOU | Intermodal Tank Transport | | | RSRV |
| 53 | IHOU | INTERMODAL TANK TRANSPORT INC | | | SCAC4 |
| 54 | IHP | INAER Helicopter Portugal Lda | Name changed to Babcock Mission Critical Services Portugal Lda. | P | AVCODES |
| 55 | IHP | Babcock Mission Critical Services Portugal Lda. | Name changed from INAER Helicopter Portugal Lda. | P | AVCODES |
| 56 | IHPP | INTERNATIONAL SHIPPING AGENCY INC. | | | SCAC4 |
| 57 | IHRC | Wabash & Erie R.R. | added 1/1995 | | NAKINA |
| 58 | IHRC | Indiana Hi-Rail Corp. | added 4/1995; eliminated 7/1998; 7/2000-7/2005 | | NAKINA |
| 59 | IHRC | Indiana Hi-Rail Corp. | added 4/1982; 1/1994; eliminated 1/1995 | | NAKINA |
| 60 | IHRC | Indiana Hi-Rail Corp. | added 4/82; 1/94; eliminated 1/95 | | NRHS |
| 61 | IHRC | Wabash & Erie R.R. | added 1/95 | | NRHS |
| 62 | IHRC | Indiana Hi-Rail Corp. | added 4/95; eliminated 7/98; 7/2000 | | NRHS |
| 63 | IHRC | INDIANA HI-RAIL CORP. [(WAER) WABASH & ERIE RAILROAD] | | | PWRC |
| 64 | IHRC | Indiana Hi-Rail Corporation | | | RSRV |
| 65 | IHRC | Indiana Hi-Rail Corp. | | USA | TRAFFIC |
| 66 | IHS | Thyrluthjonustan | | IS | AVCODES |
| 67 | IHS | Thryluthjonustan | | | ICAO1 |
| 68 | IHS | IG Historischer Schienenverkehr e.V. | Schierwaldenrath | D | privat-bahn.de |
| 69 | IHSE | I H S ENTERPRISES INC | | | SCAC4 |
| 70 | IHSX | Western Vancouver Island Heritage Society (Alberni Pacific Ry.) | 7/2000-7/2005 (not listed) | | NAKINA |
| 71 | IHSX | Western Vancouver Island Heritage Society (Alberni Pacific Ry.) | Jul-00 | | NRHS |
| 72 | IHSX | WESTERN VANCOUVER ISLAND HERITAGE SOCIETY (ALBERNI PACIFIC RAILWAY) | | | PWRC |
| 73 | IHSX | Alberni Pacific Railway (Western Vancouver Island Heritage Society) | | | RSRV |
| 74 | IHSX | WESTERN VANCOUVER ISLAND INDUSTRIAL | | | SCAC4 |
| 75 | IHTA | IRON HORSE TRANSPORTATION | | | SCAC4 |
| 76 | IHTD | IRON HORSE TRUCKING INC | | | SCAC4 |
| 77 | IHTM | IRON HAWK TRUCKING INC | | | SCAC4 |
| 78 | IHTO | INTERSTATE HAZMAT TRANSPORT INC | | | SCAC4 |
| 79 | IHTR | IRON HORSE TRUCKING LLC | | | SCAC4 |
| 80 | IHTS | IRON HORSE TRUCK SHUTTLE LTD | | | SCAC4 |
| 81 | IHTU | ITC HOLLAND TRANSPORT B.V | | NL | BIC |
| 82 | IHTU | ITC HOLLAND TRANSPORT BV | | | SCAC4 |
| 83 | IHXP | IRON HORSE EXPRESS INC | | | SCAC4 |
| 84 | IHXX | IRON HIGHWAY, INC. | | | PWRC |
