| 301 | HMTX | Hyman Michaels Tank Line (General American Transportation Corp.) | Apr-38 | | NRHS |
| 302 | HMTX | GENERAL AMERICAN TRANSPORTATION CORP. [LIQUIDS DESPATCH LINE, INC.] (HYMAN MICHAELS TANK LINE, INC.) | | | PWRC |
| 303 | HMUD | HAMCO UNITED INC | | | SCAC4 |
| 304 | HMUL | HMU LLC | | | SCAC4 |
| 305 | HMUV | HUERTA, MANUEL TRUCKING INC | | | SCAC4 |
| 306 | HMV | Homac Aviation | | | ICAO1 |
| 307 | HMVA | H MOVING & STORAGE INC | | | SCAC4 |
| 308 | HMVI | HEALY MOVERS INC | | | SCAC4 |
| 309 | HMVQ | HILFORD MOVING & STORAGE INC | | | SCAC4 |
| 310 | HMWB | HERITAGE MILLWORK & WINDOWS LTD | | | SCAC4 |
| 311 | HMWC | HALTER, MICHAEL W LLC | | | SCAC4 |
| 312 | HMWL | H & M WHOLESALE INC | | | SCAC4 |
| 313 | HMWS | HARDI INC | | | SCAC4 |
| 314 | HMWX | Heckett MultiServ | 7/2005 (not listed) | | NAKINA |
| 315 | HMWX | HECKETT MULTISERV | | | PWRC |
| 316 | HMWX | Heckett MultiServ | | | RSRV |
| 317 | HMWX | HECKETT MULTISERV | | | SCAC4 |
| 318 | HMX | Hawk de Mexico S.A. de C.V. | Callsign: Hawk Mexico, | MEX | AVCODES |
| 319 | HMX | Hawk De Mexico | | | ICAO1 |
| 320 | HMX | Hyman-Michaels Co., a Division of Azcon Corp. | added 4/1977; 1/1980; eliminated 4/1984 | | NAKINA |
| 321 | HMX | Hyman-Michaels Co. | 7/1930-1/1975; eliminated 4/1977 | | NAKINA |
| 322 | HMX | Hyman-Michaels Co. | 4/38-1/75 | | NRHS |
| 323 | HMX | Hyman-Michaels Co., a Division of Azcon Corp. | 1/80; eliminated 4/84 | | NRHS |
| 324 | HMX | HYMAN-MICHAELS CO., DIV. AZCON CORP. | | | PWRC |
| 325 | HMXC | HOLMER TRANSPORT INC | | | SCAC4 |
| 326 | HMXD | HOLMES TRANSPORT LTD | | | SCAC4 |
| 327 | HMXI | HOMELAND EXPRESS INC | | | SCAC4 |
| 328 | HMXL | HAMMTRANS LLC | | | SCAC4 |
| 329 | HMXO | HOMAX OIL SALES INC | | | SCAC4 |
| 330 | HMXT | HAMMONDS TRANSPORT | | | SCAC4 |
| 331 | HMY | HMY Airways, Inc. | IATA: HQ, Callsign: Harmony, Name changed to HMY Airways, Inc. d/b/a Harmony Airways | CDN | AVCODES |
| 332 | HMY | HMY Airways, Inc. d/b/a Harmony Airways | IATA: HQ, Callsign: Harmony, Founded in 2002. Ceased operationon 09 April 2007. Name changed from HMY Airways, Inc. | CDN | AVCODES |
| 333 | HMY | Harmony Airways | IATA: HQ | | ICAO1 |
| 334 | HMYQ | HAMMONDS | | | SCAC4 |
| 335 | HMZ | Nigerian International Air Services Limited (Hamzair) | Callsign: Hamzair, | WAN | AVCODES |
