| 1 | HX | Hickok Oil Corp. | 7/1932-1/1946 | NAKINA | |
| 2 | HX | Hickok Oil Corp. (General American Tank Car Corp.) | 7/1930 | NAKINA | |
| 3 | HX | Hickok Oil Corp. | Apr-38 | NRHS | |
| 4 | HX | HICKOK OIL CORP. 9GENERAL AMERICAN TANK CAR CO.) | PWRC | ||
| 5 | HX | Heathrow Express | 1999: standard gauge, electrified at 25kV 50Hz. The Heathrow Express service between London Paddington station and Heathrow Airport is operated by BAA plc, the airport authority. From June 1997 trains are operated between Paddington and the entrance of the tunnel under the airport, every 15 minutes. | GB | TRAFFIC |
| 6 | HX | Heathrow Express | UK | VKM | |
| 7 | HXA | China Express Airlines | ICAO1 | ||
| 8 | HXA | Hamburg Airlines | Real: HX | D | TRAFFIC |
| 9 | HXAL | HELENS TRANSPORTATION LLC | SCAC4 | ||
| 10 | HXCC | HORNS EXPRESS | SCAC4 | ||
| 11 | HXCU | TIANJIN HUAXI TRADE & TRANSPORTATIO | SCAC4 | ||
| 12 | HXIC | HIGHLANDER XPRES INC | SCAC4 | ||
| 13 | HXLH | HERSON XPRESS LLC | SCAC4 | ||
| 14 | HXLI | HOUTEX LOGISTICS INC | SCAC4 | ||
| 15 | HXLL | HX LOGISTICS LLC | SCAC4 | ||
| 16 | HXLP | HOLLINGSWORTH EXPEDITING LANE PARTN | SCAC4 | ||
| 17 | HXNT | HEXION TRANSPORTATION INC | SCAC4 | ||
| 18 | HXPE | HARLAN XPRESS | SCAC4 | ||
| 19 | HXSI | HAMNER TRANSPORTATION SYSTEMS INC | SCAC4 | ||
| 20 | HXTL | HOOSON, ADAM TRANSPORT LTD | SCAC4 | ||
| 21 | HXTW | H TWO (H2) EXPRESS | SCAC4 |