| 1 | H | Hungary | | H | TRAFFIC |
| 2 | H&BT | Huntington & Broad Top Mountain R.R. & Coal Co. | 1/1941-7/1954 | | NAKINA |
| 3 | H&BT | HUNTINGTON & BROAD TOP MOUNTAIN RAILROAD & COAL CO. | | | PWRC |
| 4 | H&BV | Houston & Brazos Valley Ry. (Co.) | 7/1923-7/1954 | | NAKINA |
| 5 | H&BV | Houston & Brazos Valley Ry. | 4/38-1/52 | | NRHS |
| 6 | H&BV | HOUSTON & BRAZOS VALLEY RWY. CO. | | | PWRC |
| 7 | H&BY | Houston & Brazos Valley Ry. | 8/1920 | | NAKINA |
| 8 | H&BY | HOUSTON & BRAZOS VALLEY RWY. CO. | | | PWRC |
| 9 | H&SW | Halifax and Southwestern Ry. (Canadian National Rys.) | 8/1920-7/1923 | | NAKINA |
| 10 | H&SW | CANADIAN NATIONAN RAILWAY [HALIFAX & SOUTHWESTERN RWY.] | | | PWRC |
| 11 | H&TC | Houston & Texas Central R.R. | 4/1938-7/1954 | | NAKINA |
| 12 | H&TC | Houston & Texas Central R.R. (Southern Pacific Lines in Texas and Louisiana) | 7/1932-7/1936 | | NAKINA |
| 13 | H&TC | Houston & Texas Central R.R. (Southern Pacific Lines in Texas and Louisiana/Southern Pacific Lines West of Portland, Ogden, El Paso and Tucumcari) | 7/1930 | | NAKINA |
| 14 | H&TC | Houston & Texas Central R.R. (Southern Pacific Lines in Texas and Louisiana) | 8/1920-7/1923 | | NAKINA |
| 15 | H&TC | Houston & Texas Central R.R. | 4/38-1/52 | | NRHS |
| 16 | H&TC | HOUSTON & TEXAS CENTRAL RAILROAD (SOUTHERN PACIFIC LINES IN TEXAS & LOUISIANA) | | | PWRC |
| 17 | H0 | 1:87 | | | TRAFFIC |
| 18 | H1 | Hahn Air Systems | Computer Reservations Systems (CRS) | D | AVCODES |
| 19 | H2 | City Bird | ICAO: CTB, Callsign: Dream Flight, Ceased operations on 04 October 2001. Designator H2* reinstated by IATA | B | AVCODES |
| 20 | H2 | Sky Service S.A. | ICAO: SKU, Callsign: Aerosky, IATA Prefix: 605, Name changed to Sky Service S.A. d/b/a Sky Airlines | RCH | AVCODES |
| 21 | H2 | City Bird | ICAO: CTB, Callsign: Dream Flight, Designator H2* recalled by IATA | B | AVCODES |
| 22 | H2 | Sky Service S.A. d/b/a Sky Airline | ICAO: SKU, Callsign: Aerosky, IATA Prefix: 605, Name changed to Sky Airline S.A. previously changed from Sky Service S.A. | RCH | AVCODES |
| 23 | H2 | Sky Airline S.A. | ICAO: SKU, Callsign: Aerosky, IATA Prefix: 605, Name changed from Sky Service S.A. d/b/a Sky Airlines | RCH | AVCODES |
| 24 | H3 | Harbour Air Ltd. | Designator H3 recalled by IATA | CDN | AVCODES |
| 25 | H3 | Saga Airlines | ICAO: SGX, Founded in 2004. Ceased operations during 2013. | TR | AVCODES |
| 26 | H3 | Hello Airlines Limited | IPSSL Group | BD | AVCODES |
| 27 | H3 | Thomas Cook Aviation GmbH | ICAO: TCN, Callsign: Nautilus, Name changed from Air Berlin Aviation GmbH on 22 November 2018. | D | AVCODES |
| 28 | H3 | Hello Jets S.r.l. | ICAO: HLJ, Callsign: Hellojets, Subsidiary of Blue Air's owner Teodor Rada. | RO | AVCODES |
| 29 | H4 | Inter Islands Airlines | ICAO: IIN, Designator H4 reinstated by IATA | CV | AVCODES |
| 30 | H4 | Hainan Airlines Company Limited | ICAO: CHH, Callsign: Hainan, IATA designator changed to HX | PRC | AVCODES |
| 31 | H4 | Heli Securite Helicopter Airline | ICAO: HLI, Callsign: Heli Saint-Tropez, Designator H4 recalled by IATA. | F | AVCODES |
| 32 | H4 | Seven Four Eight Air Services (K) Limited | ICAO: IHO, Callsign: Sefeas, IATA Prefix: 874, IATA designator changed to FE. | EAK | AVCODES |
| 33 | H4 | Raven Air, LLC d/b/a Island Hoppers Aerial Adventures | Designator H4 recalled by IATA. | USA | AVCODES |
| 34 | H4 | HiSky Europe | ICAO: HYS, Callsign: Sky Europe, | RO | AVCODES |
| 35 | H5 | Magadan Airlines | ICAO: MVL, Callsign: Mavial, IATA Prefix: 428, Designator H5 recalled by IATA | RUS | AVCODES |
| 36 | H5 | European Coastal Airlines Ltd. | ICAO: ECB, Callsign: Coastal Clipper, IATA designator changed to WL | HR | AVCODES |
| 37 | H5 | Baleares Link Express S.L. t/a Hola Airlines | ICAO: HOA, Callsign: Hola, Ceased operations on 15 February 2010. Formed by ex management from Air Europa Express | E | AVCODES |
| 38 | H5 | The Airline iFly | ICAO: RSY, Callsign: Russian Sky, Designator H5 recalled by IATA | RUS | AVCODES |
| 39 | H5 | Haiti Aviation S.A. | ICAO: HAD, | RH | AVCODES |
| 40 | H5 | Thomas Cook Airlines Balearics S.L. | ICAO: CTB, Callsign: Sunnyheart, Established in October 2017. Ceased operations on 31 January 2021 | E | AVCODES |
| 41 | H6 | Airline Chelyabinsk Air Enterprise Joint Stock Company | ICAO: CHB, Callsign: Cheravia, | RUS | AVCODES |
| 42 | H6 | Hageland Aviation Services, Inc | ICAO: HAG, Callsign: Hageland, Founed in 1981. Rebranded as Era Alaska in 2009. | USA | AVCODES |
| 43 | H6 | Bulgarian Air Charter Ltd. | ICAO: BUC, Callsign: Bulgarian Charter, Name changed to European Air Charter. | BG | AVCODES |
| 44 | H6 | Hageland Aviation Services, Inc | ICAO: HAG, Callsign: Hageland, Filed for Chapter 11 Bankruptcy, temporarily ceased all operations on 05 April 2020. Founed in 1981. Rebranded as Era Alaska in 2009. | USA | AVCODES |
| 45 | H6 | European Air Charter Ltd. | ICAO: BUC, Callsign: Eurocharter, Name changed from Bulgarian Air Charter. ICAO callsign changed from Bulgarian Charter. | BG | AVCODES |
| 46 | H7 | Air Alfa Havayollan Ve Tie A.S. | ICAO: LFA, IATA Prefix: 770, Suspended operations on 17 November 2002. Designator H7 reinstated by IATA | TR | AVCODES |
| 47 | H7 | Eagle Air Ltd. | ICAO: EGU, Callsign: African Eagle, Designator H7* reinstated by IATA / Name changed from Eagle Aviation Uganda | EAU | AVCODES |
| 48 | H7 | Edelweiss Holdings, Inc. d/b/a Rio Grande Air | ICAO: GRN, IATA designator changed to E2* | USA | AVCODES |
| 49 | H7 | Eagle Aviation Uganda | ICAO: EGU, Callsign: African Eagle, Designator H7* reinstated by IATA / Name changed to Eagle Air Ltd. | EAU | AVCODES |
| 50 | H7 | Taquan Air Services, Inc. | IATA designator changed to K3* | USA | AVCODES |
| 51 | H7 | Taron-Avia LLC | ICAO: TRV, Callsign: Taronavia, IATA Prefix: 379, Ceased operations in November 2019. Designator K7* recalled by IATA | AM | AVCODES |
| 52 | H7 | CA HiSky SRL | ICAO: HYM, Callsign: Sky Moldova, | MD | AVCODES |
| 53 | H8 | Khabarovsk Aviation Group | ICAO: KHB, Callsign: Khabarovsk Air, Name changed to Dalavia - Far East Airways - Khabarovsk | RUS | AVCODES |
| 54 | H8 | Hesa Airlines | ICAO: SON, Callsign: Sepahan, Name changed to Sepahan Airlines during 2011. | IR | AVCODES |
| 55 | H8 | Chilejet S.A. | ICAO: JMR, Ceased operations | RCH | AVCODES |
| 56 | H8 | Sky Airline Peru S.A.C. | ICAO: SKX, Callsign: Sky Peru, | PE | AVCODES |
| 57 | H8 | Sepahan Airlines | ICAO: SPN, Callsign: Sepahan, Founded in 2010. Ceased operations during 2014. Name changed from Hesa Airlines during 2011. | IR | AVCODES |
| 58 | H9 | TAM Express S/A | ICAO: SUL, Callsign: TAM Express, Name changed from Helisul Linhas Aereas S.A. | BR | AVCODES |
| 59 | H9 | Haiti Aviation S.A. d/b/a Air D'Ayiti | ICAO: HAD, Callsign: Haiti Avia, Designator H9 reinstated by IATA | RH | AVCODES |
| 60 | H9 | Helisul Linhas Aereas S.A. | ICAO: SUL, IATA designator changed from PE*. Name changed to TAM Express S/A | BR | AVCODES |
| 61 | H9 | Pegasus Hava Tasimaciligi A.S. | ICAO: PGT, Callsign: Sunturk, IATA Prefix: 624, IATA designator changed to PC. IATA designator previously changed from 1I | TR | AVCODES |
| 62 | H9 | Helitt Lineas Aereas | ICAO: HTH, Callsign: Alboran, | E | AVCODES |
| 63 | H9 | Himalaya Airlines Pvt. Ltd. | ICAO: HIM, Callsign: Himalaya, IATA Prefix: 769, Established on 20 Aug 2014. Formerly known as Yeti International Pvt. Ltd. Joint venture between HIF Aviation Company Pvt Ltd and Tibet Airlines Ltd. | NEP | AVCODES |
| 64 | HA | Hawaiian Airlines | ICAO: HAL, Callsign: Hawaiian, IATA Prefix: 173, | USA | AVCODES |
| 65 | HA | Al-Haya Aviation | ICAO: HYA, Callsign: Alhaya, IATA Prefix: 164, | IRQ | AVCODES |
| 66 | HA | Hjørring - Ålbæk | 1925 | DK | jernbanen.dk |
| 67 | HA | Nan Demo Hashiru | | | TRAFFIC |
| 68 | HAA | Helicopteros Agroforestal Ltda | Callsign: Agroforestal, | RCH | AVCODES |
| 69 | HAA | Harrison Air | Callsign: Harrison, | CDN | AVCODES |
| 70 | HAA | Helicopteros Agroforestal | | | ICAO1 |
| 71 | HAAA | HARI STONES LIMITED | | | SCAC4 |
| 72 | HAAB | HAAB, F C COMPANY INC | | | SCAC4 |
| 73 | HAAF | HALL AND SMITH ENERGY | | | SCAC4 |
| 74 | HAAG | HAAG FOODS & POULTRY INC | | | SCAC4 |
| 75 | HAAG | Haagse Tramweg Maatschappij | Real: HTM, City: Den Haag | NL | TRAFFIC |
| 76 | HAAO | HARE, J H & ASSOCIATES LTD | | | SCAC4 |
| 77 | HAARGAZ | Haargaz Group | | IL | TRAFFIC |
| 78 | HAAU | SAMAT INTERNATIONAL AB | | S | BIC |
| 79 | HAAU | ADR-HAANPAA OY | | | SCAC4 |
| 80 | HAAW | HANSON, GREG TRUCKING | | | SCAC4 |
| 81 | HAB | Ashab, Joint-Stock Air Company | Callsign: Askhab, | RUS | AVCODES |
| 82 | HAB | AirSprint US, Inc. | Callsign: Fracjet, ICAO designator changed to FCJ. | USA | AVCODES |
| 83 | HABA | HAY HAULERS UNLIMITED | | | SCAC4 |
| 84 | HABA | Stadtwerke Osnabrück AG (Hafenbahn Osnabrück) | Real: SWO | D | TRAFFIC |
| 85 | HABB | HAB NAB TRUCKING INC | | | SCAC4 |
| 86 | HABC | HALL BROS. TRANSPORTATION CO | | | SCAC1 |
| 87 | HABE | HARDEBECK TRANSPORT INC | | | SCAC4 |
| 88 | HABG | HARROD TRUCKING | | | SCAC4 |
| 89 | HABM | HART, BRIAN ANIMAL EXCHANGE | | | SCAC4 |
| 90 | HABU | AMERICA-AFRICA-EUROPE LINE GMBH | | | SCAC3 |
| 91 | HABU | HARY GMBH | | | SCAC4 |
| 92 | HABX | Habco International Inc. | 1/1994-7/2005 (not listed) | | NAKINA |
| 93 | HABX | Habco, Inc. | added 1/1972; 1/1975-1/1980; eliminated 5/1983 | | NAKINA |
| 94 | HABX | Horne-Boatright Chemical Co., Inc. | added 4/1969; 4/1970; eliminated 1/1972 | | NAKINA |
| 95 | HABX | Hanlon-Buchanan, Inc. | 7/1935-1/1946 | | NAKINA |
| 96 | HABX | Hanlon-Buchanan, Inc. | Apr-38 | | NRHS |
| 97 | HABX | Horne-Boatright Chemical Co., Inc. | added 4/69; 4/70; eliminated 1/72 | | NRHS |
| 98 | HABX | Habco, Inc. | added 1/72; 1/75-1/80; eliminated 5/83 | | NRHS |
| 99 | HABX | Habco International Inc. | 1/94-7/2000 | | NRHS |
| 100 | HABX | *HANLON-BUCHANAN, INC. | | | PWRC |
