| 1 | NAP | Napier Air Service, Inc. | Callsign: Napier, | USA | AVCODES |
| 2 | NAP | Napier Air Service Inc | | | ICAO1 |
| 3 | NAP | The Narragansett Pier R.R. Co., Inc. | 1/1975-1/1980; eliminated 10/1986; added 10/1987; eliminated 7/1989; 1/1994-7/2005 | | NAKINA |
| 4 | NAP | The Narragansett Pier R.R. Co., Inc. | 1/75-1/80; eliminated 10/86; added 10/87; eliminated 7/89; 1/94-7/2000 | | NRHS |
| 5 | NAP | NARRAGANSETT PIER RAILROAD CO. | | | PWRC |
| 6 | NAP | Narragansett Pier Railroad | | | RSRV |
| 7 | NAP | Fábrica Nitrato de Amónio de Portugal, S.A. | | PT | VKM |
| 8 | NAPA | NAPA CHARTER LINES | | | SCAC3 |
| 9 | NAPA | NAPA CHARTER LINES | | | SCAC4 |
| 10 | NAPB | NATIONAL PIGGYBACK CINCINNATI INC | | | SCAC3 |
| 11 | NAPC | NEWMAN AND PEMBERTON CORPORATION | | | SCAC3 |
| 12 | NAPE | NAPIER, ROBERT C, TRUCKING, INC | | | SCAC3 |
| 13 | NAPE | NAPOLEON EXPRESS LTD | | | SCAC4 |
| 14 | NAPK | NATIONAL PARK CONCESSIONS INC | | | SCAC3 |
| 15 | NAPL | NAPOLITANO, G TRUCKING CORP | | | SCAC3 |
| 16 | NAPL | NEVADO ARTISTIC PLASTER LTD | | | SCAC4 |
| 17 | NAPN | NATIONAL AUTOMATIC PIPELINE OPERATO | | | SCAC3 |
| 18 | NAPO | NAPOGA TRILLIUM TRANSPORT | | | SCAC4 |
| 19 | NAPOLI | Azienda Napoletana Mobilitá SPA. | Real: ANM, City: Napoli | I | TRAFFIC |
| 20 | NAPP | NAP & PAULS BOAT TRANSPORT LTD | | | SCAC3 |
| 21 | NAPP | NAP & PAULS BOAT TRANSPORT LTD | | | SCAC4 |
| 22 | NAPQ | NAPLES TRUCKING COMPANY | | | SCAC3 |
| 23 | NAPR | NAPORANO IRON & METAL CO | | | SCAC3 |
| 24 | NAPS | NEWSOME, A P & SONS | | | SCAC4 |
| 25 | NAPT | NAPPI TRUCKING CORPORATION | | | SCAC3 |
| 26 | NAPU | NAVIERA PACIFICO CA | | | SCAC3 |
| 27 | NAPU | NAVIERA PACIFICO CA | | | SCAC4 |
| 28 | NAPV | NAZARETH TRANSPORT SERVICES | | | SCAC3 |
| 29 | NAPW | NAVIERA AMAZONICA PERUANA S A | | | SCAC3 |
| 30 | NAPW | NAVIERA AMAZONICA PERUANA S A | | | SCAC4 |
| 31 | NAPX | North American Plastics, Inc. | added 10/1995; 7/2000-7/2005 | | NAKINA |
| 32 | NAPX | North American Plastics, Inc. | added 10/95; 7/2000 | | NRHS |
| 33 | NAPX | NORTH AMERICAN PLASTICS INCORPORATED | | | PWRC |
| 34 | NAPX | North American Plastics | | | RSRV |