| 1 | HZ | Sakhalinskie Aviatrassy, SAT | ICAO: SHU, Callsign: Satair, IATA Prefix: 598, Merged with Vladivostok Air to form Aurora. IATA designator changed from GZ*. Designator HZ reinstated by IATA | RUS | AVCODES |
| 2 | HZ | Thurston Aviation Ltd. d/b/a Tal-Air | ICAO: THG, Callsign: Thurston, Name reverted back to Thurston Aviation Ltd. Formerly Thurston Aviation Ltd. | GB | AVCODES |
| 3 | HZ | Thurston Aviation Ltd. | ICAO: THG, Callsign: Thurston, Name changed to Thurston Aviation Ltd. d/b/a Tal-Air | GB | AVCODES |
| 4 | HZ | Thurston Aviation Ltd. | ICAO: THG, Callsign: Thurston, Designator recalled by IATA. Formerly Tal-Air | GB | AVCODES |
| 5 | HZ | Herts and Essex Aero Club Ltd. | Callsign: Hartex, | GB | AVCODES |
| 6 | HZ | Joint- Stock Company "Aurora Airlines" | ICAO: SHU, Callsign: Satair, IATA Prefix: 598, ICAO callsign changed to Aurora. | RUS | AVCODES |
| 7 | HZ | Joint- Stock Company "Aurora Airlines" | ICAO: SHU, Callsign: Aurora, IATA Prefix: 598, ICAO callsign changed from Satair. | RUS | AVCODES |
| 8 | HZ | | | HR | TRAFFIC |
| 9 | HZ | Hrvatske Željeznice | | HR | VKM |
| 10 | HZA | Horizon Airlines Pty Ltd. | IATA: BN, Callsign: Horiz Air, IATA designator changed from YK* / Designator HK* recalled by IATA | AUS | AVCODES |
| 11 | HZA | Horizon Airlines Pty Ltd. | IATA: KH, Callsign: Horiz Air, IATA designator changed from YK* / Designator HK* recalled by IATA | AUS | AVCODES |
| 12 | HZA | Horizon Airlines | IATA: BN | | ICAO1 |
| 13 | HZAI | HZT INTERNATIONAL INC | | | SCAC4 |
| 14 | HZAR | HUZAR LOGISITCS INC | | | SCAC4 |
| 15 | HZBN | HERNANDEZ, BENJAMIN | | | SCAC4 |
| 16 | HZCAR | HŽ CARGO d.o.o. | | HR | VKM |
| 17 | HZCH | HERNANDEZ ORTIZ, JOSE ALFREDO | | | SCAC4 |
| 18 | HZCI | HERNANDEZ RUIZ, ARTURO | | | SCAC4 |
| 19 | HZEC | HORIZON ENTERTAINMENT CARGO CO | | | SCAC4 |
| 20 | HZEG | HAZMAT ENVIRONMENTAL GROUP INC | | | SCAC4 |
| 21 | HZEL | HAZEL TRUCKING CORPORATION | | | SCAC4 |
| 22 | HZEN | HAZEN TRANSPORT INC | | | SCAC4 |
| 23 | HZEP | HINZ ENTERPRISES LLC | | | SCAC4 |
| 24 | HZER | HAZER ENTERPRISES INC | | | SCAC4 |
| 25 | HZFU | HANGZHOU FINE FLUOROTECH CO., LTD | | PRC | BIC |
| 26 | HZGT | HERZOG TRUCKING INC | | | SCAC4 |
| 27 | HZGV | HERNANDEZ GARCIA, VIOLETA | | | SCAC4 |
| 28 | HZGX | Herzog Contracting Corp. | added 7/1991; 1/1994-7/2005 | | NAKINA |
| 29 | HZGX | Herzog Contracting Corp. | added 7/91; 1/94-7/2000 | | NRHS |
| 30 | HZGX | HERZOG CONTRACTING CORPORATION | | | PWRC |
| 31 | HZGX | Herzog Contracting Corporation | | | RSRV |
| 32 | HZGX | HERZOG RAILROAD SERVICES INC | | | SCAC4 |
| 33 | HZHS | HAZELS HOTSHOT SERVICE | | | SCAC4 |
| 34 | HZIU | HITACHI ZOSEN INOVA BIOMETHAN GMBH | | D | BIC |
| 35 | HZJE | HERNANDEZ, JUAN E INC | | | SCAC4 |
| 36 | HZKL | HOUTZ TRUCKING LLC | | | SCAC4 |
| 37 | HZKU | HZ KONTEJNERY S.R.O. | | CZ | BIC |
| 38 | HZL | Hazelton Airlines | IATA: ZL, Callsign: Hazelton, IATA Prefix: 899, Name changed to Hazelton Airlines d/b/a Rgional Express | AUS | AVCODES |
| 39 | HZL | Hazelton Airlines d/b/a Regional Express | IATA: ZL, Callsign: Hazelton, IATA Prefix: 899, Designator ZL recalled by IATA. Name changed from Hazelton Airlines | AUS | AVCODES |
| 40 | HZL | Hazelton Airlines | | | ICAO1 |
| 41 | HzL | Hohenzollerische Landesbahn AG | Hechingen | D | privat-bahn.de |
| 42 | HZL | Hohenzollerische Landesbahn AG | | D | TRAFFIC |
| 43 | HZL | Hohenzollerische Landesbahn | | DE | VKM |
| 44 | HZLA | Hazelton Airlines | | AUS | TRAFFIC |
| 45 | HZLC | HORIZON LOGISTICS LLC | | | SCAC4 |
| 46 | HZLG | HAZMAT LOGISTICS INC | | | SCAC4 |
| 47 | HZLS | HORIZON LIMOUSINE SERVICE | | | SCAC4 |
| 48 | HZM | Huzima | Callsign: Huzima, | EC | AVCODES |
| 49 | HZMA | HORIZON MOTOR COACH INC | | | SCAC4 |
| 50 | HZMC | HORIZON MARINE CORPORATION | | | SCAC4 |
| 51 | HZMG | HORIZON MOVING & STORAGE | | | SCAC4 |
| 52 | HZN | Horizon Airlines Pty Ltd. | IATA: YK, IATA designator changed to KH*. Name changed from International Aviation Pty. Ltd. | AUS | AVCODES |
| 53 | HZN | Horizon Airlines Ltd. | Callsign: Horiz Air, | WAN | AVCODES |
| 54 | HZNA | HORIZON AIR SERVICES INC | | | SCAC4 |
| 55 | HZND | HORIZON DISTRIBUTION INC | | | SCAC4 |
| 56 | HZNF | HORIZON FREIGHT SYSTEM INC | | | SCAC4 |
| 57 | HZNL | HOLTZMAN PROPANE LLC | | | SCAC4 |
| 58 | HZNS | HORIZONA SHIPPING CO LTD MALTA | | | SCAC4 |
| 59 | HZNT | HINZ TRUCKING INC | | | SCAC4 |
| 60 | HZNV | HORIZON VAN LINES INC | | | SCAC4 |
| 61 | HZOP | HUAZO TRANSPORT | | | SCAC4 |
| 62 | HZPP | HŽ Putnički prijevoz | | HR | TRAFFIC |
| 63 | HZPP | HŽ PUTNIČKI PRIJEVOZ d.o.o. | | HR | VKM |
| 64 | HZPR | HAZPRO TRANSPORTATION LLC | | | SCAC4 |
| 65 | HZR | LOT Polish Airlines S.A. | Callsign: Huzar, | PL | AVCODES |
| 66 | HZRA | HERNANDEZ RODRIGUEZ, ALBERTO | | | SCAC4 |
| 67 | HZRD | HERTZ, ROGER TRUCKING INC | | | SCAC4 |
| 68 | HZRK | HERNANDEZ, R TRUCKING | | | SCAC4 |
| 69 | HZS | Aviation Horizons Ltd. | Callsign: Horizon Sky, | SA | AVCODES |
| 70 | HZT | Air Horizon | Callsign: Horizon Togo, | TG | AVCODES |
| 71 | HZT | Air Horizon | IATA: 8C | | ICAO1 |
| 72 | HZTG | HORIZON TRANSPORTATION SERVICES/HTS | | | SCAC4 |
| 73 | HZTI | HORIZON TRANSPORT INC | | | SCAC4 |
| 74 | HZTN | HORIZON TESTING INC | | | SCAC4 |
| 75 | HZTO | HORZEN, T REFRIGERATED TRANSPORT IN | | | SCAC4 |
| 76 | HZTP | HORIZON TRANSPORTATION INC | | | SCAC4 |
| 77 | HZTS | HORIZON TRANSPORTATION SERVICES INC | | | SCAC4 |
| 78 | HZUS | HARTWELL DZUS SA DE CV | | | SCAC4 |
| 79 | HZVB | Harzer Verkehrsbetriebe GmbH | Real: HVB | D | TRAFFIC |
| 80 | HZVV | HŽ VUČA VLAKOVA | | HR | VKM |
| 81 | HZX | CITIC General Aviation Co., Ltd | Callsign: Zhongxin Air, | PRC | AVCODES |
| 82 | HZX | Citic General Aviation | | | ICAO1 |
| 83 | HZX | The Hegeler Zinc Co. | 8/1920-7/1954; eliminated 1/1955 | | NAKINA |
| 84 | HZX | The Hegeler Zinc Co. | 4/38-1/52 | | NRHS |
| 85 | HZX | HEGELER ZINC CO. | | | PWRC |
| 86 | HZY | Hainan Lily Jet Co., Ltd. | Callsign: Air Lily, | PRC | AVCODES |
| 87 | HZZM | HAZZARD MOVING & STORAGE CO | | | SCAC4 |
