| 6501 | SLV | Federal Carriers, Inc. | Callsign: Sullivan, | USA | AVCODES |
| 6502 | SLV | Stella Aviation | | | ICAO1 |
| 6503 | SLV | Shortline Väst | 1994 - 2001 | S | svenska-lok.se |
| 6504 | SLV | Shortline Väst | 1994 - 2001 | S | TRAFFIC |
| 6505 | SLVA | SILVA, STANLEY G TRUCKING INC | | | SCAC4 |
| 6506 | SLVAG | Slov-Vagon, a.s. | | SK | TRAFFIC |
| 6507 | SLVAG | SLOV-VAGON, a.s. | | SK | VKM |
| 6508 | SLVB | SILVA BAUTISTA, ABAD | | | SCAC4 |
| 6509 | SLVD | SILVERADO EXPRESS INC | | | SCAC4 |
| 6510 | SLVG | SILVERLINING TRANSPORT LTD | | | SCAC4 |
| 6511 | SLVJ | SILVA OROZCO, JOSE AMPARO | | | SCAC4 |
| 6512 | SLVK | STEVES LIVESTOCK TRANSPORTATION (BL | | | SCAC4 |
| 6513 | SLVL | SILVERLINING TRUCKING INC | | | SCAC4 |
| 6514 | SLVM | SILVA MARTINEZ, RAMON | | | SCAC4 |
| 6515 | SLVN | SULLIVAN, R. M., TRANSPORTATION, INC | | | SCAC1 |
| 6516 | SLVQ | SILVA TRUCKING INC | | | SCAC4 |
| 6517 | SLVS | SULLIVAN MOVING AND STORAGE CO | | | SCAC1 |
| 6518 | SLVS | SULLIVAN MOVING & STORAGE | | | SCAC4 |
| 6519 | SLVT | SILVER STAR TRANSPORTATION LTD | | | SCAC4 |
| 6520 | SLVU | SEALEAD SHIPPING DMCC | | UAE | BIC |
| 6521 | SLVV | SLOVER MOVING & STORAGE | | | SCAC4 |
| 6522 | SLVX | Silver Enterprises | 7/2000 (not listed) | | NAKINA |
| 6523 | SLVX | Silver Enterprises Associates Inc. | 7/2005 | | NAKINA |
| 6524 | SLVX | Silver Enterprises | Jul-00 | | NRHS |
| 6525 | SLVX | SILVER ENTERPRISES ASSOCIATES INC. | | | PWRC |
| 6526 | SLVX | Silver Enterprises | | | RSRV |
| 6527 | SLVX | SILVER ENTERPRISE ASSOCIATES INC | | | SCAC4 |
| 6528 | SLVY | SELF LEVELING MACHINES | | | SCAC4 |
| 6529 | SLVY | Solvay Bulgaria AD / Солвей България АД | | BG | VKM |
| 6530 | SLW | Salama Airlines Nigeria Limited | Callsign: Salma Air, | WAN | AVCODES |
| 6531 | SLW | Salama Airlines Nigeria | | | ICAO1 |
| 6532 | SLWC | Stillwater Central R.R. Co., Inc. | 7/2000-7/2005; added 4/2006 | | NAKINA |
| 6533 | SLWC | Stillwater Central R.R. Co., Inc. | Jul-00 | | NRHS |
| 6534 | SLWC | STILLWATER CENTRAL RAILROAD COMPANY | | | PWRC |
| 6535 | SLWC | Stillwater Central Railroad | | | RSRV |
| 6536 | SLWC | STILLWATER CENTRAL RAILROAD COMPANY | | | SCAC4 |
| 6537 | SLWE | SLW TRUCKING | | | SCAC4 |
| 6538 | SLWG | SAUNDERS JR, L W TRUCKING INC | | | SCAC4 |
| 6539 | SLWJ | SEALWELL INC | | | SCAC4 |
| 6540 | SLWL | STARLINE WINDOWS (2001) LTD | | | SCAC4 |
| 6541 | SLWO | SWALLOW OIL CO | | | SCAC4 |
| 6542 | SLWQ | SPARTACUS LOGISTICS INC | | | SCAC4 |
| 6543 | SLWR | SELDOMRIDGE WRECKER SERVICE | | | SCAC4 |
| 6544 | SLWS | SLW EXPRESS | | | SCAC4 |
| 6545 | SLWU | SALTWORKS TECHOLOGIES INC | | CDN | BIC |
| 6546 | SLWU | Saltworks Techologies | | | RSRV |
| 6547 | SLWV | SUTER, LEO TRUCKING | | | SCAC4 |
| 6548 | SLWW | SPECTRUM LOGISTICS | | | SCAC4 |
| 6549 | SLWX | Santa Lucia Wineries, Inc. | 7/1935 | | NAKINA |
| 6550 | SLWY | SILICON ROADWAYS | | | SCAC4 |
| 6551 | SLX | Sky Line Airlines | Callsign: Slatour, | KZ | AVCODES |
| 6552 | SLX | American Aircraft International, Inc. | Callsign: Shuttle Express, | USA | AVCODES |
| 6553 | SLX | Sete Linhas Aereas | | | ICAO1 |
| 6554 | SLXA | STALLION EXPRESS INC | | | SCAC4 |
| 6555 | SLXB | STREAM LINKS EXPRESS INC | | | SCAC4 |
| 6556 | SLXC | SELECT EXPRESS LLC | | | SCAC4 |
| 6557 | SLXE | SOUTHLAND EXPRESS | | | SCAC4 |
| 6558 | SLXH | SUMMERA | | | SCAC4 |
| 6559 | SLXI | SEACON LOGIX INC | | | SCAC4 |
| 6560 | SLXJ | STEEL LINE TRANSPORT | | | SCAC4 |
| 6561 | SLXK | SHORT HAUL TRUCKING | | | SCAC4 |
| 6562 | SLXL | SLT EXPRESS, INC | | | SCAC1 |
| 6563 | SLXL | SLT EXPRESS INC | | | SCAC4 |
| 6564 | SLXM | SALLEE TRANSPORT | | | SCAC4 |
| 6565 | SLXN | SNOLINE EXPRESS INC | | | SCAC4 |
| 6566 | SLXO | STI | | | SCAC4 |
| 6567 | SLXP | SONLITE EXPRESS INCORPORATED | | | SCAC4 |
| 6568 | SLXQ | SMART LINE EXPRESS INC | | | SCAC4 |
| 6569 | SLXS | SHORELINE EXPRESS INC | | | SCAC4 |
| 6570 | SLXT | SLOAN TRANSPORTATION | | | SCAC4 |
| 6571 | SLXU | Stewart Lubricants & Service Co | | | RSRV |
| 6572 | SLXU | STEWART LUBRICANTS & SERVICE CO, IN | | | SCAC4 |
| 6573 | SLXV | SILT LEASING & TRANSPORTATION SERVI | | | SCAC4 |
| 6574 | SLXY | SAMUEL TRANSPORT | | | SCAC4 |
| 6575 | SLY | Sky Line For Air Services Ltd. | Callsign: Skyco, | SUD | AVCODES |
| 6576 | SLY | Sky Line for Air Services | | | ICAO1 |
| 6577 | SLYA | SLY TRANSPORTATION LLC | | | SCAC4 |
| 6578 | SLYD | SCOTLYNN COMMODITIES INC | | | SCAC4 |
| 6579 | SLYF | SLAYTON FUEL CO LLC | | | SCAC4 |
| 6580 | SLYG | SCHMITT, LARRY TRUCKING INC | | | SCAC4 |
| 6581 | SLYH | SCOTT, LYNN H INC | | | SCAC4 |
| 6582 | SLYL | SKYLINE LOGISTICS INC | | | SCAC4 |
| 6583 | SLYM | SOLYM CARRIERS LIMITED | | | SCAC4 |
| 6584 | SLYN | SEALY MATTRESS CO | | | SCAC4 |
| 6585 | SLYP | SEA LADY SHIPPING & TRADING S A | | | SCAC4 |
| 6586 | SLYQ | SKYLINE HELICOPTERS LTD | | | SCAC4 |
| 6587 | SLYT | STANLEYS TRUCKING LLC | | | SCAC4 |
| 6588 | SLYW | SIMAS LOGISTICS LLC | | | SCAC4 |
| 6589 | SLYY | SEBASTAINS LOGISTICS INC | | | SCAC4 |
| 6590 | SLZ | Super Luza | Callsign: Luza, | ANG | AVCODES |
| 6591 | SLZ | Super Luza | | | ICAO1 |
| 6592 | SLZC | SOURCE LOGISTICS LLC | | | SCAC4 |
| 6593 | SLZD | SALAZAR ESPRONCEDA, DANIEL | | | SCAC4 |
| 6594 | SLZE | SILOZ-EXPRESS SA DE CV | | | SCAC4 |
| 6595 | SLZHN | SLZ CHÉMIA, a.s. | | SK | VKM |
| 6596 | SLZJ | STALLINGS TOURS LLC | | | SCAC4 |
| 6597 | SLZK | STELZER TRUCKING | | | SCAC4 |
| 6598 | SLZL | SALAZAR LOPEZ, MARISOL | | | SCAC4 |
| 6599 | SLZN | S & L TRADE INC | | | SCAC4 |
| 6600 | SLZP | SELECT PROPANE INC | | | SCAC4 |
