| 1 | LPN | Laoag International Airlines | IATA: L7, Callsign: Laoag Air, Ceased operations in 2006 | RP | AVCODES |
| 2 | LPN | Laoag International Airlines | IATA: L7 | | ICAO1 |
| 3 | LPN | Longview, Portland & Northern Ry. Co. | 1/1975; added 7/1977; 1/1980-7/2000; eliminated 10/2000 | | NAKINA |
| 4 | LPN | Longview, Portland & Northern Ry. Co. | 1/75; added 7/77; 1/80-7/2000; eliminated 10/2000 | | NRHS |
| 5 | LPN | LONGVIEW, PORTLAND & NORTHERN RAILWAY COMPANY | | | PWRC |
| 6 | LPN | Longview, Portland and Northern Railway | | | RSRV |
| 7 | LPN | Longview, Portland and Northern Railway | | USA | TRAFFIC |
| 8 | LPNL | LEP INTERNATIONAL BV | | | SCAC3 |
| 9 | LPNQ | LES PECHERIES NORREF QUEBEC INC | | | SCAC4 |
| 10 | LPNS | LIEN, PETE & SONS INC | | | SCAC3 |
| 11 | LPNT | LAPLANT MOVING AND STORAGE COMPANY | | | SCAC3 |
| 12 | LPNW | LEP INTERNATIONAL LTD | | | SCAC3 |
| 13 | LPNX | LEHIGH NORTHWEST CEMENT LTD. | | | PWRC |
| 14 | LPNX | LEHIGH NORTHWEST CEMENT LIMITED | | | SCAC4 |
