| 1 | HLP | Helipistas, S.L. | Callsign: Helipistas, | E | AVCODES |
| 2 | HLP | Helipistas | | | ICAO1 |
| 3 | HLP | Traditionsgemeinschaft Bw Halle P e.V. | | DE | VKM |
| 4 | HLPA | HALPIN TRUCKING | | | SCAC4 |
| 5 | HLPG | HELLESPONT GRAND CORPORATION | | | SCAC4 |
| 6 | HLPL | HILL PETROLEUM | | | SCAC4 |
| 7 | HLPX | Otter Tail Power Co. | added 1/2005; 7/2005 | | NAKINA |
| 8 | HLPX | Houston Lighting & Power Co. | 1/1950-1/1980; eliminated 5/1983 | | NAKINA |
| 9 | HLPX | Houston Lighting & Power Co. | 1/52-1/80; eliminated 5/83 | | NRHS |
| 10 | HLPX | *HOUSTON LIGHTING & POWER CO. | | | PWRC |
| 11 | HLPX | +OTTER TAIL POWER CO. | | | PWRC |
| 12 | HLPX | Houston Lighting and Power | | | RSRV |
| 13 | HLPX | OTTER TAIL POWER CO | | | SCAC4 |
| 14 | HLPY | TAR HEEL OIL II INCDBA HALL PETROLE | | | SCAC4 |
| 15 | HLPZ | HOUSTON LIGHTING & POWER CO. | | | PWRC |
