| 101 | HDL | Hastings Diesels Limited | | UK | VKM |
| 102 | HDLA | HIRSCH DEVELOPMENTS LTD | | | SCAC4 |
| 103 | HDLC | HENDRIX AND DAIL INC | | | SCAC4 |
| 104 | HDLE | HASKELL, DUSTY L | | | SCAC4 |
| 105 | HDLG | HEARTLAND LOGISTICS LLC | | | SCAC4 |
| 106 | HDLK | H D L ENTERPRISES INC | | | SCAC4 |
| 107 | HDLM | HOOFBEATS DISTRIBUTION LIMITED | | | SCAC4 |
| 108 | HDLO | HENDEL'S INCORPORATED | | | SCAC4 |
| 109 | HDLP | HAPPY DAYS LEISURE PRODUCTS LIMITED | | | SCAC4 |
| 110 | HDLR | HIDALGO ROCHIN, MARCOS ABRAHAM | | | SCAC4 |
| 111 | HDLT | H D L TRANSPORT INC | | | SCAC4 |
| 112 | HDLU | SAFMARINE CONTAINER LINES NV | | | SCAC4 |
| 113 | HDLX | Helm Diamond Rail Leasing | added 10/2008 | | NAKINA |
| 114 | HDLX | HELM DIAMOND RAIL LEASING | | | PWRC |
| 115 | HDM | Harley-Davidson Motor Company | Callsign: Hog, | USA | AVCODES |
| 116 | HDM | Hudson & Manhattan | 1/1975-1/1980 | | NAKINA |
| 117 | HDM | Hudson & Manhattan | 1/75-1/80 | | NRHS |
| 118 | HDM | HUDSON & MANHATTAN | | | PWRC |
| 119 | HDM | Hudson and Manhattan | | | RSRV |
| 120 | HDM | Hudson & Manhattan | | US-NY | TRAFFIC |
| 121 | HDMC | HARDI MIDWEST INC | | | SCAC4 |
| 122 | HDMI | HANDEI MACK INC | | | SCAC4 |
| 123 | HDMO | HALLIBURTON DE MEXICO | | | SCAC4 |
| 124 | HDMS | HOLIDAY TRANSFER CO | | | SCAC4 |
| 125 | HDMT | HARDEMAN TRUCKING | | | SCAC4 |
| 126 | HDMU | HMM CO., LTD. | | ROK | BIC |
| 127 | HDMU | HYUNDAI MERCHANT MARINE (AMERICA), INC. | | | PWRC |
| 128 | HDMU | Hyundai Merchant Marine (America) | | | RSRV |
| 129 | HDMU | HYUNDAI MERCHANT MARINE (AMERICA) INC | | | SCAC1 |
| 130 | HDMU | HYUNDAI MERCHANT MARINE | | | SCAC4 |
| 131 | HDMZ | HYUNDAI MERCHANT MARINE (AMERICA), INC. | | | PWRC |
| 132 | HDMZ | Hyundai Merchant Marine (America) | | | RSRV |
| 133 | HDMZ | HYUNDAI MERCHANT MARINE (AMERICA), | | | SCAC4 |
| 134 | HDNA | HARMON, DONALD C TRUCKING | | | SCAC4 |
| 135 | HDNO | HOLDENS OIL INC | | | SCAC4 |
| 136 | HDNP | HUDSON SHIPPING LINES CORP NY | | | SCAC4 |
| 137 | HDNQ | HIDDEN VALLEY MOVING & STORAGE INC | | | SCAC4 |
| 138 | HDNR | HOLLISTER, DON R TRUCKING | | | SCAC4 |
| 139 | HDNS | HARRIS, DICK & SON TRUCKING CO INC | | | SCAC4 |
| 140 | HDNV | HUDSON VALLEY LOGISTICS LIMITED | | | SCAC4 |
| 141 | HDNW | HERSON DISTRIBUTION NETWORK INC | | | SCAC4 |
| 142 | HDOE | HAMILTON, DOUG | | | SCAC4 |
| 143 | HDOI | HEIL, DON OIL CO INC | | | SCAC4 |
| 144 | HDOL | HARDY OIL CO INC | | | SCAC4 |
| 145 | HDON | HODGDON BROS & SONS INC | | | SCAC4 |
| 146 | HDOP | HOODS OIL COMPANY INC | | | SCAC4 |
| 147 | HDOT | HONDO TRUCKING INC | | | SCAC4 |
| 148 | HDPL | HAND, PAUL | | | SCAC4 |
| 149 | HDPU | HIMDILING PRO LTD | | RUS | BIC |
| 150 | HDR | Helikopterdrift AS | Callsign: Helidrift, Name changed to Helitrans AS. ICAO callsign changed to Helitrans. | N | AVCODES |
| 151 | HDR | Helitrans AS | Callsign: Helitrans, Name changed from Helikopterdrift AS. ICAO callsign changed to Helitdrift. | N | AVCODES |
| 152 | HDR | Helikopterdrift | | | ICAO1 |
| 153 | HDRC | HANDRICH TRUCKING INC | | | SCAC4 |
| 154 | HDRI | HOOD TRANSPORTATION | | | SCAC4 |
| 155 | HDRK | HINDRIKS, GEORGE | | | SCAC4 |
| 156 | HDRM | HEIDMAR INC | | | SCAC4 |
| 157 | HDRN | HENDRICKSON TRANSPORTATION LLC | | | SCAC4 |
| 158 | HDRQ | H D R | | | SCAC4 |
| 159 | HDRT | HYDRA TRANSPORT | | | SCAC4 |
| 160 | HDRX | Helm Diamond Rail Leasing | added 10/2008 | | NAKINA |
| 161 | HDRX | HELM DIAMOND RAIL LEASING | | | PWRC |
| 162 | HDS | UEF Historischer Damfschnellzug e.V | | DE | VKM |
| 163 | HDSA | HERITAGE DEDICATED SERVICES INC | | | SCAC4 |
| 164 | HDSB | HDS EXPRESS | | | SCAC4 |
| 165 | HDSC | HENDERSCHIED | | | SCAC4 |
| 166 | HDSD | HACKBARTH DELIVERY SERVICE INC | | | SCAC4 |
| 167 | HDSF | HUMPTY DUMPTY SNACK FOODS USA INC | | | SCAC4 |
| 168 | HDSG | HARRIS DATA STORAGE INC | | | SCAC4 |
| 169 | HDSH | HD SHIPPING LTD | | | SCAC4 |
| 170 | HdSJ | Härnösand - Sollefteå Järnväg | 1893 - 1932 | S | svenska-lok.se |
| 171 | HDSK | H-D-SOUCY INC | | | SCAC4 |
| 172 | HDSL | HENDERSON LOGISTIC | | | SCAC4 |
| 173 | HDSO | HARDISON TRANSPORTATION LLC | | | SCAC4 |
| 174 | HDSP | HYLAND, SEAN MOTORSPORT | | | SCAC4 |
| 175 | HDSS | HDS EXPRESS LINES | | | SCAC4 |
| 176 | HDSU | HAYS DISTRIBUTION SERVICES LTD | | | SCAC4 |
| 177 | HDSX | The CIT Group/Capital Finance, Inc. | added 10/2003; 7/2005 | | NAKINA |
| 178 | HDSX | RailAmerica Equipment Corp. | added 10/1996; 7/2000; eliminated 1/2003 | | NAKINA |
| 179 | HDSX | Huron Distribution Services/Rail America Equipment Corp. | added 7/1996; eliminated 10/1996 | | NAKINA |
| 180 | HDSX | Huron Distribution Services | 1/1994 (not listed) | | NAKINA |
| 181 | HDSX | H.D. Schrier | added 7/1961; 7/1965; eliminated 7/1966; added 4/1967; 4/1970; eliminated 10/1974 | | NAKINA |
| 182 | HDSX | H.D. Schrier | 7/65; eliminated 7/66; added 4/67; 4/70; eliminated 10/74 | | NRHS |
| 183 | HDSX | Huron Distribution Services | Jan-94 | | NRHS |
| 184 | HDSX | Huron Distribution Services/Rail America Equipment Corp. | added 7/96; eliminated 10/96 | | NRHS |
| 185 | HDSX | RailAmerica Equipment Corp. | added 10/96; 7/2000 | | NRHS |
| 186 | HDSX | *H. D. SCHRIER | | | PWRC |
| 187 | HDSX | *HURON DISTRIBUTION SERVICES | | | PWRC |
| 188 | HDSX | +THE CIT GROUP/CAPITAL FINANCE [RAIL AMERICA EQUIPMENT CORP.] | | | PWRC |
| 189 | HDSX | RailAmerica Equipment Corporation | | | RSRV |
| 190 | HDSX | CIT GROUP/CAPITAL FINANCE INC, THE | | | SCAC4 |
| 191 | HDSY | HUNTE DELIVERY SYSTEM INC | | | SCAC4 |
| 192 | HDT | HOT DOGGER TOURS INC | | | SCAC4 |
| 193 | HDTB | HEAVY DUTY TRANSPORT | | | SCAC4 |
| 194 | HDTC | HURD, TRACEY | | | SCAC4 |
| 195 | HDTD | HEAVY DUTY TRUX LTD | | | SCAC4 |
| 196 | HDTE | HOLIDAY TREE FARMS INC | | | SCAC4 |
| 197 | HDTH | HALVERSON, DAN TRUCKING | | | SCAC4 |
| 198 | HDTI | HERMAN, DANNY TRUCKING INC | | | SCAC4 |
| 199 | HDTK | HOOD TRUCKING | | | SCAC4 |
| 200 | HDTM | H D T | | | SCAC4 |
