| 6201 | SLIL | SANTICO LIFE | | | SCAC4 |
| 6202 | SLIN | STEVENS LINE COMPANY | | | SCAC4 |
| 6203 | SLIQ | SATELLITE AIR LAND MOTOR SERVICE, INC | | | SCAC1 |
| 6204 | SLIQ | SATELLITE AIR LAND MOTOR SERVICE IN | | | SCAC4 |
| 6205 | SLIT | SOLUCIONES LOGISTICAS INTERNACIONAL | | | SCAC4 |
| 6206 | SLIU | SEAPORT LINES INDIA PRIVATE LIMITED | | IND | BIC |
| 6207 | SLIU | STAR LINES EQUIPMENT, INC. | | | PWRC |
| 6208 | SLIU | Star Lines Equipment | | | RSRV |
| 6209 | SLIU | SEAWAYS SHIPPING LTD | | | SCAC4 |
| 6210 | SLIX | St. Louis Independent Packing Co. | 7/1923-7/1930 | | NAKINA |
| 6211 | SLIX | ST. LOUIS INDEPENDENT PACKING CO. | | | PWRC |
| 6212 | SLIY | SELIN, WAYNE | | | SCAC4 |
| 6213 | SLIZ | STAR LINES SHIPPING COMPANY, INC | | | PWRC |
| 6214 | SLIZ | Star Lines Shipping | | | RSRV |
| 6215 | SLIZ | AVENIDA QUINTA | | | SCAC3 |
| 6216 | SLIZ | STAR LINES SHIPPING COMPANY, INC | | | SCAC4 |
| 6217 | SLJ | Slam Lavori Aerei S.R.L. | Callsign: Slamair, | I | AVCODES |
| 6218 | SLJB | SUNLINE LTD | | | SCAC4 |
| 6219 | SLJC | SCREENWORKS LLC LIVE POWER | | | SCAC4 |
| 6220 | SLJG | SOUTHERN LOGISTICS INC | | | SCAC4 |
| 6221 | SLJH | SYNERGY LOGISTICS LLC | | | SCAC4 |
| 6222 | SLJL | SIERRA LOGISTICS INC | | | SCAC4 |
| 6223 | SLJQ | SLATON, JAMES, TRUCKING | | | SCAC1 |
| 6224 | SLJU | SEATRADE CHARTERING N.V. | | NL | BIC |
| 6225 | SLJU | STREAMLINES NV | | | SCAC4 |
| 6226 | SLJV | SUNTECK LOGISTIC INC | | | SCAC4 |
| 6227 | SLJW | SOUTHWEST LANDMARK INC | | | SCAC4 |
| 6228 | SLJY | S & L TRANSPORTATION SERVICE INC | | | SCAC4 |
| 6229 | SLK | SilkAir (S) Pte. Ltd. | IATA: MI, Callsign: Silkair, IATA Prefix: 629, Name changed to SilkAir (SINGAPORE) Pte. Ltd. | SGP | AVCODES |
| 6230 | SLK | Independent Air, Inc. | Callsign: Skylark, | USA | AVCODES |
| 6231 | SLK | Independent Air, Inc. | Callsign: Skylark, ICAO designator changed to IDN | USA | AVCODES |
| 6232 | SLK | SilkAir (SINGAPORE) Pte. Ltd. | IATA: MI, Callsign: Silkair, IATA Prefix: 629, Merged into Singapore Airlines. Name changed from SilkAir (S) Pte. Ltd. | SGP | AVCODES |
| 6233 | SLK | SilkAir | IATA: MI | | ICAO1 |
| 6234 | SLK | SilkAir Singapore Private Limited | | SGP | TRAFFIC |
| 6235 | SLKA | SLOVACEK SAUSAGE CO | | | SCAC4 |
| 6236 | SLKB | S & L TRUCKING | | | SCAC4 |
| 6237 | SLKC | SALLEY, K C VAN & STORAGE | | | SCAC4 |
| 6238 | SLKD | SILK ROAD ENTERPRISES LTD | | | SCAC4 |
| 6239 | SLKE | SALT LAKE AIR CARGO | | | SCAC4 |
| 6240 | SLKG | SEA-LINK MARINE GROUP OF | | | SCAC4 |
| 6241 | SLKK | SOHAL TRUCKING | | | SCAC4 |
| 6242 | SLKL | SUN LINK LOGISTICS CO L | | | SCAC4 |
| 6243 | SLKN | SERVICE LINK TRANSPORT INC | | | SCAC4 |
| 6244 | SLKR | SILK ROAD TRANSLINK INC | | | SCAC4 |
| 6245 | SLKT | SALT LAKE TRANSFER COMPANY | | | SCAC1 |
| 6246 | SLKT | SALT LAKE TRANSFER CO (A UT CORP) | | | SCAC4 |
| 6247 | SLKU | SEA-LINK CONTAINER LINES | | | PWRC |
| 6248 | SLKU | Sea-Link Container Lines | | | RSRV |
| 6249 | SLKW | STONE LAKE OIL | | | SCAC4 |
| 6250 | SLL | Slovak Airlines, Inc. | IATA: 6Q, Callsign: Slov Line, IATA Prefix: 921, IATA designator changed from 9S | SK | AVCODES |
| 6251 | SLL | Saarland Airlines | IATA: QW, Callsign: Saarland, Designator SX recalled by IATA. Declared bankrupt 28 July 1993. | D | AVCODES |
| 6252 | SLL | Slovak Airlines | IATA: 9S, IATA designator changed to 6Q | SK | AVCODES |
| 6253 | SLL | Skylink Aviation Limited | | EAK | AVCODES |
| 6254 | SLL | Slovak Airlines | IATA: 6Q | | ICAO1 |
| 6255 | SLLD | S T L TRANSPORTATION & LOGISTICS IN | | | SCAC4 |
| 6256 | SLLE | STELLER & SONS LLC | | | SCAC4 |
| 6257 | SLLL | SOUTHLAKE LOGISTICS LLC | | | SCAC4 |
| 6258 | SLLM | ST LOGISTICS LLC | | | SCAC4 |
| 6259 | SLLO | S & L LOGISTICS INC | | | SCAC4 |
| 6260 | SLLS | SEAL LEASING LLC | | | SCAC4 |
| 6261 | SLLU | SEA-LAND LOGISTICS ENTERPRISES PTE LTD | | SGP | BIC |
| 6262 | SLLU | SEAWAY LINES, INC. | | | SCAC4 |
| 6263 | SLLV | SULLIVANS TRUCKING LTD | | | SCAC4 |
| 6264 | SLLX | ST. LOUIS & LAKE COUNTIES REGIONAL RAILROAD | | | PWRC |
| 6265 | SLM | Surinam Airways Ltd. | IATA: PY, Callsign: Surinam, IATA Prefix: 192, | SME | AVCODES |
| 6266 | SLM | Surinam Airways | IATA: PY | | ICAO1 |
| 6267 | SLM | | | CH | TRAFFIC |
| 6268 | SLMAG | Slovmag a.s. | | SK | VKM |
| 6269 | SLMB | St. Louis Merchants Bridge Terminal Ry. Co. | 8/1920 | | NAKINA |
| 6270 | SLMB | St. Louis Merchants Bridge Terminal Ry. Co. (Terminal R.R. Association of St. Louis) | 7/1923-7/1930 | | NAKINA |
| 6271 | SLMB | TERMINAL RAILROAD ASSOCIATION OF STY. LOUIS [ST. LOUIS MUNICIPAL BRIDGE TERMINAL RAILWAY] | | | PWRC |
| 6272 | SLMB | SLOMINS INC | | | SCAC4 |
| 6273 | SLMC | SUWANNNEE LUMBER MANUFACTURING CO I | | | SCAC4 |
| 6274 | SLMD | SLIMLINE MANUFACTURING LTD | | | SCAC4 |
| 6275 | SLMI | SALAS, MARCELINO | | | SCAC4 |
| 6276 | SLMJ | SMITH, LORNE INC | | | SCAC4 |
| 6277 | SLML | SURE LINE MARINE LLC | | | SCAC4 |
| 6278 | SLMM | SCHLIMME | | | SCAC4 |
| 6279 | SLMR | STERLING MOVING & STORAGE INC | | | SCAC4 |
| 6280 | SLMT | STARLINE MULTI-TRANS SERVICES LTD | | | SCAC4 |
| 6281 | SLMU | LLC «SILMAR SHIPPING» | | RUS | BIC |
| 6282 | SLMU | GOLD CONTAINER CORP | | | SCAC4 |
| 6283 | SLMV | SUNLAND MOVING SERVICES INC | | | SCAC4 |
| 6284 | SLMX | The Sugar Land Manufacturing Co. | 8/1920 | | NAKINA |
| 6285 | SLMX | SUGAR LAND MANUFACTURING CO. | | | PWRC |
| 6286 | SLMY | SUGAR LAND COURIER SERVICES | | | SCAC4 |
| 6287 | SLN | Sloane Aviation Ltd. | Callsign: Sloane, | GB | AVCODES |
| 6288 | SLN | Sloane Helicopters | Callsign: Sloane, | GB | AVCODES |
| 6289 | SLN | Sloane Aviation | | | ICAO1 |
| 6290 | SLND | SOUTHLAND-DALLAS | | | SCAC4 |
| 6291 | SLNH | STALLION TRUCKING | | | SCAC4 |
| 6292 | SLNI | SCHOELLERMAN, RON TRUCKING INC | | | SCAC4 |
| 6293 | SLNO | SOLENO INC | | | SCAC4 |
| 6294 | SLNP | SLOMAN NEPTUN SHIPPING & TRANSPORT | | | SCAC4 |
| 6295 | SLNU | SELINA SHIPPING LINES PTE. LTD. | | SGP | BIC |
| 6296 | SLNV | SHORELINE TANK SERVICES LTD | | | SCAC4 |
| 6297 | SLNY | S LINE TRANSPORTATION INC | | | SCAC4 |
| 6298 | SLO | Edgartown Air, Inc. | Callsign: Slow, | USA | AVCODES |
| 6299 | SLO | Slocum Air, Inc. | Callsign: Slocum, | USA | AVCODES |
| 6300 | SLO | Edgartown Air | | | ICAO1 |
