| 1 | SS | Corse Air International | ICAO: CRL, Callsign: Corsair, IATA Prefix: 923, IATA designator changed from CS. ICAO callsign changed from Charlie Sierra | F | AVCODES |
| 2 | SS | Transportes Aereos Nacionales De Selva (TANS) | IATA designator changed to TJ* | PE | AVCODES |
| 3 | SS | Transportes Aereos Nacionales de Selva (TANS) | ICAO: ELV, Callsign: Aereos Selva, IATA designator changed to TJ* | PE | AVCODES |
| 4 | SS | Saggitair Limited | Callsign: Sagittair, Name changed to Sagittair Limited. | GB | AVCODES |
| 5 | SS | Sagitair Limited | Callsign: Sagittair, Name changed from Saggittair Limited. | GB | AVCODES |
| 6 | SS | Aerolineas Dominicanas S.A. | ICAO: ADM, Callsign: Dominair, | DOM | AVCODES |
| 7 | SS | Sand Springs Ry. Co. | 1/1975-1/1980; added 1/1994; 7/2000-7/2005 | | NAKINA |
| 8 | SS | Sand Springs Ry. Co. | 1/75-1/80; added 1/94; 7/2000 | | NRHS |
| 9 | SS | SAND SPRINGS RAILWAY COMPANY | | | PWRC |
| 10 | SS | Sand Springs Railway | | | RSRV |
| 11 | SS | SAND SPRINGS RAILWAY COMPANY | | | SCAC4 |
| 12 | SS | Staatsspoorwegen (State Railways) | | NL | TRAFFIC |
| 13 | SSA | Sisav | Callsign: Sisav, | I | AVCODES |
| 14 | SSAA | SALT SPRING AIR | | | SCAC4 |
| 15 | SSAB | SSAB Tunnplåt AB | | SE | VKM |
| 16 | SSAC | SS TRUCKING | | | SCAC4 |
| 17 | SSAG | SSB TRUCKING LTD | | | SCAC4 |
| 18 | SSAK | SMYTH MOVING SERVICE OF ALASKA INC | | | SCAC4 |
| 19 | SSAL | SOTO SALAS, GERARDO | | | SCAC4 |
| 20 | SSAM | Sault Ste. Marie Bridge Co. | added 4/1993; 1/1994-7/2005 | | NAKINA |
| 21 | SSAM | Sault Ste. Marie Bridge Co. | added 4/93; 1/94-7/2000 | | NRHS |
| 22 | SSAM | SAULT STE. MARIE BRIDGE COMPANY (WISCONSIN CENTRAL SUBSIDIARY) | | | PWRC |
| 23 | SSAM | Sault Ste. Marie Bridge (Wisconsin Central) | | | RSRV |
| 24 | SSAM | SAULT STE MARIE BRIDGE | | | SCAC4 |
| 25 | SSAN | STUART, S ANTIQUES | | | SCAC4 |
| 26 | SSANG | Ssangyong Cement Industrial Co. | | ROK | TRAFFIC |
| 27 | SSAP | SOS TRANSPORTATION LLC | | | SCAC4 |
| 28 | SSAT | SOLANO GONZALEZ, SANTIAGO | | | SCAC4 |
| 29 | SSAV | SECURITY STORAGE AND VAN COMPANY | | | SCAC4 |
| 30 | SSAY | SOUTHERN STEAMSHIP AGENCY INC | | | SCAC4 |
| 31 | SSB | Sasair, Inc. | Callsign: Sasair, | CDN | AVCODES |
| 32 | SSB | California Seaboard Airlines, Inc. | Callsign: Cal Seaboard, | USA | AVCODES |
| 33 | SSB | Suasa Airlines Sdn Bhd | IATA: R9, Callsign: Suasa Air, Ceased operations. | MAL | AVCODES |
| 34 | SSB | Sasair | | | ICAO1 |
| 35 | SSB | | City: Stuttgart | D | TRAFFIC |
| 36 | SSBD | SUNDANCE SEAFOOD LTD | | | SCAC4 |
| 37 | SSBF | SOSEBEE FREIGHT LINE, INC | | | SCAC1 |
| 38 | SSBJ | SCOTT STREET TOMATO HOUSE INC | | | SCAC4 |
| 39 | SSBL | SELECT SHOWS BLUE UNIT LTD | | | SCAC4 |
| 40 | SSBO | SMOOTH SHIPPING | | | SCAC4 |
| 41 | SSBQ | SAN SILVESTRE FLETES Y ACARREOS | | | SCAC4 |
| 42 | SSBR | SBS SPECIALIZED INC | | | SCAC4 |
| 43 | SSBR | SSB Reisen | | D | TRAFFIC |
| 44 | SSBT | SILVER STREAK BOATS LTD | | | SCAC4 |
| 45 | SSBU | SPECIALIST SERVICES LLC | | UAE | BIC |
| 46 | SSBU | SPECIALIST SERVICES LLC | | | SCAC4 |
| 47 | SSBV | SEPSA S A DE CV | | | SCAC4 |
| 48 | SSBX | Sun Shipbuilding Co. | 8/1920 | | NAKINA |
| 49 | SSBX | SUN SHIPBUILDING CO. | | | PWRC |
| 50 | SSBY | STANSHIPS INC | | | SCAC4 |
| 51 | SSC | Southern Skies Commuter Co. | Callsign: Southern Skies, Name changed to Southern Seaplane, Inc. | USA | AVCODES |
| 52 | SSC | Southern Seaplane, Inc. | Callsign: Southern Skies, Name changed from Southern Skies Commuter Co. | USA | AVCODES |
| 53 | SSC | Southern Seaplane | | | ICAO1 |
| 54 | SSC | Southern Switching Co. | added 1/1995; eliminated 7/1996; 7/2000-7/2005 | | NAKINA |
| 55 | SSC | Southern Switching Co. | added 1/95; eliminated 7/96; 7/2000 | | NRHS |
| 56 | SSC | SOUTHERN SWITCHING COMPANY (STOCKYARDS SERVICE COMPANY) | | | PWRC |
| 57 | SSC | Southern Switching | | | RSRV |
| 58 | SSC | SOUTHERN SWITCHING COMPANY | | | SCAC4 |
| 59 | SSCA | SEVEN SEAS CARRIERS AS | | | SCAC4 |
| 60 | SSCC | SERRA, S CHEESE CO | | | SCAC4 |
| 61 | SSCD | S S CHAD EXPRESS LLC | | | SCAC4 |
| 62 | SSCE | SUPERIOR SEAFOODS COMPANY INC | | | SCAC4 |
| 63 | SSCF | SCHNEIDER NATIONAL CARRIERS INC (CO | | | SCAC4 |
| 64 | SSCH | SUNSHINE CHARTERS INC | | | SCAC4 |
| 65 | SSCI | SECURITY STORAGE COMPANY OF CHARLOT | | | SCAC4 |
| 66 | SSCK | S & S TRUCKING | | | SCAC4 |
| 67 | SSCN | SSC TRANSPORTS INC | | | SCAC4 |
| 68 | SSCO | SHOTA SHIPPING CO.,LTD. | | | SCAC4 |
| 69 | SSCP | SOUTHERN STATES COOPERATIVE INC | | | SCAC4 |
| 70 | SSCR | SLADOVNY SOUFFLET ČR a.s. | | CZ | VKM |
| 71 | SSCS | SPECTRUM SUPPLY CHAIN SOLUTIONS INC | | | SCAC4 |
| 72 | SSCT | SISCO TRUCKING | | | SCAC4 |
| 73 | SSCU | SHANGHAI SHOWA CHEMICALS CO.LTD | | PRC | BIC |
| 74 | SSCU | STATES STEAMSHIP CO. | | | PWRC |
| 75 | SSCU | States Steamship | | | RSRV |
| 76 | SSCU | STATES STEAMSHIP COMPANY | | | SCAC4 |
| 77 | SSCX | Southern States Chemical Co. | added 7/1963; 7/1965-10/1966; eliminated 10/1967 | | NAKINA |
| 78 | SSCX | Southern Stone Co., Inc. | added 4/1971; 1/1975; eliminated 7/1979 | | NAKINA |
| 79 | SSCX | Southern States Chemical Co. | added 7/63; 7/65-10/66; eliminated 10/67 | | NRHS |
| 80 | SSCX | Southern Stone Co., Inc. | added 4/71; 1/75; eliminated 7/79 | | NRHS |
| 81 | SSCX | *STOCKYARDS SERVICE COMPANY | | | PWRC |
| 82 | SSCX | *SOUTHERN STATES CHEMICAL CO. | | | PWRC |
| 83 | SSCX | *SOUTHERN STONE CO., INC. | | | PWRC |
| 84 | SSCX | SOUTHERN STONE COMPANY | | | SCAC4 |
| 85 | SSCY | SCHAPER SERVICES CO THE | | | SCAC4 |
| 86 | SSCZ | (SSCU) STATES STEAMSHIP CO. | | | PWRC |
| 87 | SSCZ | States Steamship | | | RSRV |
| 88 | SSCZ | STATES STEAMSHIP CO. | | | SCAC4 |
| 89 | SSD | Star Service International | Callsign: Star Service, | F | AVCODES |
| 90 | SSD | Star Service International | | | ICAO1 |
| 91 | SSD | UNION PACIFIC RAILROAD COMPANY | | | PWRC |
| 92 | SSD | Union Pacific Railroad | | | RSRV |
| 93 | SSDB | SIMON & SIMON FREIGHT TRUCKING LLC | | | SCAC4 |
| 94 | SSDC | SEASIDE CARRIERS CORP | | | SCAC4 |
| 95 | SSDD | SSD DISTRIBUTION SYSTEM INC | | | SCAC4 |
| 96 | SSDE | SAFE & SECURE INDUSTRIES LLC | | | SCAC4 |
| 97 | SSDF | SERVICES SANITAIRES DENIS FORTIER I | | | SCAC4 |
| 98 | SSDI | SCHLEESE SADDLERY SERVICE LTD | | | SCAC4 |
| 99 | SSDK | Savannah State Docks R.R. Co. | 1/1975; added 4/1979; 1/1980-1/1994; eliminated 1/1999; 7/2000 | | NAKINA |
| 100 | SSDK | Savannah State Docks R.R. Co. | 1/75; added 4/79; 1/80-1/94; eliminated 1/99; 7/2000 | | NRHS |
