| 1 | HAR | Harbor Airlines | IATA: HB, Callsign: Harbor, Founded in March 1971, originally named Oak Harbor Airlines. Suspended all flights in May 2001. | USA | AVCODES |
| 2 | HAR | Harbor Airlines | IATA: HB | | ICAO1 |
| 3 | HARC | HARVEST CA | | | SCAC4 |
| 4 | HARD | HARLESS, DICK L | | | SCAC4 |
| 5 | HARE | HARRIS, CHARLES | | | SCAC4 |
| 6 | HARF | HAR-TRANS FREIGHT | | | SCAC4 |
| 7 | HARI | HARRIS, RICHARD L | | | SCAC4 |
| 8 | HARK | HARPER TRUCK LINE INC | | | SCAC4 |
| 9 | HARM | HARMUN TRUCKING INC | | | SCAC4 |
| 10 | HARO | HARMAN TRANSPORTATION | | | SCAC4 |
| 11 | HARP | HARPA | | | SCAC4 |
| 12 | HARR | HARRIER SHIPPING COMPANY LIMITED | | | SCAC4 |
| 13 | HARRIS | Harris Bus | | GB | TRAFFIC |
| 14 | HARS | HARRIS EXPRESS INC | | | PWRC |
| 15 | HART | Huntington Area Rapid Transit | | USA | TRAFFIC |
| 16 | HARTON | Harton Coal Company | | GB | TRAFFIC |
| 17 | HARU | HARBOUR RENTAL & SERVICES BV | | NL | BIC |
| 18 | HARU | CHARENTE STEAMSHIP CO., LTD | | | SCAC3 |
| 19 | HARV | HARVEY TRANSPORT LTD | | | SCAC4 |
| 20 | HARX | General Electric Rail Services Corp. | added 1/2000; 7/2000-7/2005 | | NAKINA |
| 21 | HARX | General Electric Railcar Services Corp. | added 4/1992; 1/1994; eliminated 1/2000 | | NAKINA |
| 22 | HARX | Hargis Railcar, Inc. | added 7/1989; eliminated 4/1992 | | NAKINA |
| 23 | HARX | Harcon Corp. | added 1/1964 | | NAKINA |
| 24 | HARX | Harriman Co. | 7/1930-7/1935 | | NAKINA |
| 25 | HARX | Hargis Railcar, Inc. | added 7/89; eliminated 4/92 | | NRHS |
| 26 | HARX | General Electric Railcar Services Corp. | added 4/92; 1/94; eliminated 1/2000 | | NRHS |
| 27 | HARX | General Electric Rail Services Corp. | added 1/2000; 7/2000 | | NRHS |
| 28 | HARX | *HARRIMAN CO. | | | PWRC |
| 29 | HARX | +(NATX) GENERAL ELECTRIC RAIL SERVICES CORPORATION [HARGIS RAILCAR, INC.] | | | PWRC |
| 30 | HARX | *HAWAII RAILWAY, INC. | | | PWRC |
| 31 | HARX | GE Rail Services Corporation | | | RSRV |
| 32 | HARX | GENERAL ELECTRIC RAILCAR SERVICES C | | | SCAC4 |
| 33 | HARZ | HARRISON RADIATOR | | | PWRC |
