| 5401 | SJSX | S.J. Sackett | 1/1945-1/1946 | | NAKINA |
| 5402 | SJSX | S. J. SACKETT | | | PWRC |
| 5403 | SJSZ | SPECIALTY CHASSIS LEASING, INC. | | | PWRC |
| 5404 | SJSZ | Specialty Chassis Leasing | | | RSRV |
| 5405 | SJT | Jet 2000 AB | Callsign: Swedejet, | S | AVCODES |
| 5406 | SJT | Swiss Jet Ltd. | Callsign: Swiss Jet, | CH | AVCODES |
| 5407 | SJT | Asa Jet Airlines | Callsign: Asajet Airlines, | IR | AVCODES |
| 5408 | SJT | Swiss Jet | | | ICAO1 |
| 5409 | SJT | St. Joseph Terminal R.R. Co. | 1/1975-1/1980 | | NAKINA |
| 5410 | SJT | St. Joseph Terminal R.R. Co. | 1/75-1/80 | | NRHS |
| 5411 | SJT | ST. JOSEPH TERMINAL RAILROAD | | | PWRC |
| 5412 | SJT | St. Joseph Terminal Railroad | | | RSRV |
| 5413 | SJTD | STEGER, JOHN TRUCKING LLC | | | SCAC4 |
| 5414 | SJTE | SEA JUSTICE S A | | | SCAC4 |
| 5415 | SJTG | SCHUGEL, J & R TRUCKING INC (INTERM | | | SCAC4 |
| 5416 | SJTJ | SEA-JET TRUCKING CORP | | | SCAC4 |
| 5417 | SJTL | S & J TRANSPORT LLC | | | SCAC4 |
| 5418 | SJTM | SOJITZ MARINE & ENGINEERING CORPORA | | | SCAC4 |
| 5419 | SJTN | S & J TRANSPORT LTD | | | SCAC4 |
| 5420 | SJTO | SOJITZ LOGISTICS CORPORATION | | | SCAC4 |
| 5421 | SJTP | S-J TRANSPORTATION CO INC | | | SCAC4 |
| 5422 | SJTQ | SANTIAGO, JOSE TRUCKING INC | | | SCAC4 |
| 5423 | SJTR | SJ TRUCKING LLC | | | SCAC4 |
| 5424 | SJTS | S & J TRANSPORTATION SERVICES INC | | | SCAC4 |
| 5425 | SJTT | S & J TRANSPORT | | | SCAC4 |
| 5426 | SJTU | San Juan Tren Urbano | | US-PR | TRAFFIC |
| 5427 | SJTV | SHIVERS, J TRUCKING LLC | | | SCAC4 |
| 5428 | SJTW | STERE, JEFF TRUCKING | | | SCAC4 |
| 5429 | SJTX | Stella Jones Inc. | added 7/2008 | | NAKINA |
| 5430 | SJTX | STELLA JONES, INC. | | | PWRC |
| 5431 | SJTX | STELLA JONES INC | | | SCAC4 |
| 5432 | SJU | Sky Jet | | EAU | AVCODES |
| 5433 | SJUU | S JONES CONTAINERS LTD | | GB | BIC |
| 5434 | SJV | PT. Super Air Jet | IATA: IU, Callsign: Prosper, Subsidiary of Lion Air Group. | RI | AVCODES |
| 5435 | SJVM | Banverket, Sveriges Järnvägsmuseum | | SE | VKM |
| 5436 | SJVR | San Joaquin Valley R.R. Co. | added 4/1992; 1/1994-7/2005 | | NAKINA |
| 5437 | SJVR | San Joaquin Valley R.R. Co. | added 4/92; 1/94-7/2000 | | NRHS |
| 5438 | SJVR | SAN JOAQUIN VALLEY RAILROAD CO. | | | PWRC |
| 5439 | SJVR | San Joaquin Valley Railroad | | | RSRV |
| 5440 | SJVR | SAN JOAQUIN VALLEY RAILROAD CO | | | SCAC4 |
| 5441 | SJVU | SEOJIN SYSTEM CO.,LTD | | VN | BIC |
| 5442 | SJVX | St. Joseph Viscosity Oil Co. | 8/1920-7/1923 | | NAKINA |
| 5443 | SJVX | ST. JOSEPH VISCOSITY OIL CO. | | | PWRC |
| 5444 | SJWB | SMITH, J WILLIS & BROTHER INC | | | SCAC4 |
| 5445 | SJWH | SMITH, J W | | | SCAC4 |
| 5446 | SJWN | S & J TOWING | | | SCAC4 |
| 5447 | SJWR | SAN JOSE WAREHOUSING, INC | | | SCAC1 |
| 5448 | SJWR | SAN JOSE WAREHOUSING INC | | | SCAC4 |
| 5449 | SJWT | SANCHEZ, J AND W, TRUCKING CO | | | SCAC1 |
| 5450 | SJWT | SANCHEZ, J & W TRUCKING CO INC | | | SCAC4 |
| 5451 | SJWX | Transportation Management, Inc. | 1/1975; added 4/1975; eliminated 7/1976 | | NAKINA |
| 5452 | SJWX | Missouri Valley Walnut Co. | added 7/1976; 1/1980; eliminated 1/1982 | | NAKINA |
| 5453 | SJWX | Transportation Management, Inc. | 1/75; added 4/75 | | NRHS |
| 5454 | SJWX | Missouri Valley Walnut Co. | 1/80; eliminated 1/82 | | NRHS |
| 5455 | SJWX | MISSOURI VALLEY WALNUT CO. (TRANSPORTATION MANAGEMENT, INC.) | | | PWRC |
| 5456 | SJX | Starlux Airlines Co., Ltd. | Callsign: Starwalker, Commenced operations on 23 January 2020. | RC | AVCODES |
| 5457 | SJXA | S & J TRANSPORT | | | SCAC4 |
| 5458 | SJXC | SEAJET EXPRESS CONTAINER LINE LTD | | | SCAC4 |
| 5459 | SJXF | SUPER J TRANS LLC | | | SCAC4 |
| 5460 | SJXL | SUPER J TRANSPORT LTD | | | SCAC4 |
| 5461 | SJXO | SONJA TRANSPORTATION | | | SCAC4 |
| 5462 | SJXP | ST JOE EXPRESS INC | | | SCAC4 |
| 5463 | SJXR | SJ TRANSPORT | | | SCAC4 |
| 5464 | SJXT | S & J EXPRESS TRUCKING INC | | | SCAC4 |
| 5465 | SJXU | STX PAN OCEAN CO LTD | | | SCAC4 |
| 5466 | SJY | Sriwijaya Air PT | IATA: SJ, Callsign: Sriwijaya, IATA Prefix: 977, Designator SJ reinstated by IATA | RI | AVCODES |
| 5467 | SJY | Sriwijaya Air | | | ICAO1 |
| 5468 | SJYA | SANJAYS FOODS LTD | | | SCAC4 |
| 5469 | SJYT | SWEARENGIN, JERRY TRUCKING INC | | | SCAC4 |
| 5470 | SJZU | SIZ TRANSGLOBAL AG | | | SCAC4 |
| 5471 | SJZY | SZECHYNSKI, JERZY | | | SCAC4 |
| 5472 | SK | Scandinavian Airlines System (SAS) | ICAO: SAS, Callsign: Scandinavian, IATA Prefix: 117, | S | AVCODES |
| 5473 | SK | Snowflake | ICAO: SAS, Commenced operations on 19 March 2003. Merged back into SAS 31 October 2004. Low cost business unit of SAS Scandinavian Airlines (SAS Group) | S | AVCODES |
| 5474 | SK | Siegener Kreisbahn GmbH | Siegen | D | privat-bahn.de |
| 5475 | SK | Seehafen Kiel GmbH & Co KG | Kiel | D | privat-bahn.de |
| 5476 | SK | Siegener Kreisbahn | Renamed to KSW - Kreisbahn Siegen-Wittgenstein GmbH | D | TRAFFIC |
| 5477 | SKA | Rio Air Express S/A | Callsign: Rio Express, | BR | AVCODES |
| 5478 | SKA | Skyjet Brasil | Callsign: Rio Express, | BR | AVCODES |
| 5479 | SKA | Skegness Air Taxi Services Ltd. d/b/a Skegair | Callsign: Skegair, | GB | AVCODES |
| 5480 | SKA | Rio Air Express | | | ICAO1 |
| 5481 | SKAD | SKATEBOARD EXPRESS | | | SCAC4 |
| 5482 | SKAE | SCHULTZ, KELLY ANTIQUES | | | SCAC4 |
| 5483 | SKAF | Slovak Air Force | | SK | TRAFFIC |
| 5484 | SKAG | SKAGIT FARMERS SUPPLY | | | SCAC4 |
| 5485 | SKAI | SKAR TRUCKING INC | | | SCAC4 |
| 5486 | SKAJ | Stockholms Kultursällskap för Ånga och Järnväg | | SE | VKM |
| 5487 | SKAM | SEAHAW | | | SCAC4 |
| 5488 | SKAN | SPRINGFIELD TRUCK LINE LLC | | | SCAC4 |
| 5489 | SKAND | SKAND Skalica | | SK | TRAFFIC |
| 5490 | SKANE | Skanetrafiken | | S | TRAFFIC |
| 5491 | SKANE | Skånetrafiken | | SE | VKM |
| 5492 | SKANS | Skanska a.s. | | CZ | VKM |
| 5493 | SKAP | SKYLINE DECKING LTD | | | SCAC4 |
| 5494 | SKAQ | SEA LINK TRANSPORT INC | | | SCAC4 |
| 5495 | SKAR | SASKARC INDUSTRIES INC | | | SCAC4 |
| 5496 | SKASK | Skanska SK a.s. | | SK | VKM |
| 5497 | SKAT | SKAGIT TRANSPORTATION INC | | | SCAC4 |
| 5498 | SKAU | SKAFF CRYOGENICS INC | | USA | BIC |
| 5499 | SKAU | Skaff Cryogenics | | | RSRV |
| 5500 | SKB | Skyfreighters Corp. | Callsign: Skybus, | USA | AVCODES |
