| 1 | SNC | Air Cargo Carriers, Inc. | IATA: 2Q, Callsign: Night Cargo, IATA Prefix: 883, Designator 2Q reinstated by IATA. IATA designator changed from 3U* | USA | AVCODES |
| 2 | SNC | Air Cargo Carriers, Inc. | IATA: 3U, Callsign: Night Cargo, Designator 3U* recalled by IATA | USA | AVCODES |
| 3 | SNC | Air Cargo Carriers, Inc. | IATA: 3U, Callsign: Night Cargo, IATA designator changed to 2Q. Designator 3U* reinstated by IATA | USA | AVCODES |
| 4 | SNC | Apollo Airways, Inc. | Callsign: Sonic, | USA | AVCODES |
| 5 | SNC | Air Cargo Carriers, LLC. | IATA: 2Q, Callsign: Night Cargo, Designator 2Q reinstated by IATA. IATA designator changed from 3U* | USA | AVCODES |
| 6 | SNC | Air Cargo Carriers | IATA: 2Q | | ICAO1 |
| 7 | SNC | SEATTLE & NORTH COAST RAILROAD | | | PWRC |
| 8 | SNC | Saratoga & North Creek Railway | | USA | TRAFFIC |
| 9 | SNCA | SANTOS CAMACHO, FLORENCIO | | | SCAC4 |
| 10 | SNCB | | | B | TRAFFIC |
| 11 | SNCB | Société Nationale des Chemins de fer Belges | | BE | VKM |
| 12 | SNCC | SUN COAST TRANSPORT CORPORATION | | | SCAC4 |
| 13 | SNCD | SNOW, CLAYTON D INC | | | SCAC4 |
| 14 | SNCE | SAUNACORE | | | SCAC4 |
| 15 | SNCF | SCHNEIDER NATIONAL CARRIERS INC-VAR | | | SCAC4 |
| 16 | SNCF | | | F | TRAFFIC |
| 17 | SNCF | Société Nationale des Chemins de Fer | | FR | VKM |
| 18 | SNCFA | Société Nationale des Chemins de Fer Algériens | | DZ | TRAFFIC |
| 19 | SNCFFB | SNCF Fret Benelux | | | TRAFFIC |
| 20 | SNCFT | | | TN | TRAFFIC |
| 21 | SNCFT | Société Nationale des Chemins de Fer Tunésiens | | TN | VKM |
| 22 | SNCG | STONE CENTRE GRANITE & MARBLE | | | SCAC4 |
| 23 | SNCI | S & C TRANSPORT INC | | | SCAC4 |
| 24 | SNCK | SCHNEIDER NATIONAL CARRIERS INC (TR | | | SCAC4 |
| 25 | SNCL | SUNICE LOGISTICS INC | | | SCAC4 |
| 26 | SNCM | SUNLINE COMMERCIAL CARRIERS INC | | | SCAC4 |
| 27 | SNCO | Seaport Navigation | 1/1975-1/1980 | | NAKINA |
| 28 | SNCO | Seaport Navigation | 1/75-1/80 | | NRHS |
| 29 | SNCO | SEAPORT NAVIGATION | | | PWRC |
| 30 | SNCO | SPRAY NINE CORPORATION | | | SCAC4 |
| 31 | SNCQ | STILLSON OIL CO INC | | | SCAC4 |
| 32 | SNCR | S & C TRANSPORT INC | | | SCAC4 |
| 33 | SNCR | Saratoga & North Creek Railway | | USA | TRAFFIC |
| 34 | SNCS | SCHNEIDER NATIONAL CARRIERS INC (TR | | | SCAC4 |
| 35 | SNCT | Seattle & North Coast R.R. Co. | added 4/1980; eliminated 1/1989 | | NAKINA |
| 36 | SNCT | Seattle & North Coast R.R. Co. | added 4/80; eliminated 1/89 | | NRHS |
| 37 | SNCT | SEATTLE & NORTH COAST RAILROAD | | | PWRC |
| 38 | SNCT | Seattle and North Coast Railroad | | | RSRV |
| 39 | SNCT | SONIC TRANSPORTATION | | | SCAC4 |
| 40 | SNCT | Seattle & North Coast | | USA | TRAFFIC |
| 41 | SNCU | INTERNATIONAL CONTAINER LEASE INC | | PRC | BIC |
| 42 | SNCV | | | B | TRAFFIC |
| 43 | SNCW | SUNCOAST TRANSPORT LLC | | | SCAC4 |
| 44 | SNCX | STEAMTOWN NATIONAL HISTORIC SITE | | | PWRC |
| 45 | SNCY | SCHNEIDER NATIONAL CARRIERS INC-DED | | | SCAC4 |
| 46 | SNCZ | SCHNEIDER NATIONAL LEASING | | | SCAC4 |
