| 1 | SSO | Special Scope Limited | Callsign: Dope, | GB | AVCODES |
| 2 | SSO | S&S Orinoco Aviation C.A. | Callsign: Orinoco, | YV | AVCODES |
| 3 | SSO | Special Scope Limited | | | ICAO1 |
| 4 | SSO | Städtische Straßenbahn Offenbach | City: Offenbach | D | TRAFFIC |
| 5 | SSOA | SUNSHINE OIL CO INC | | | SCAC4 |
| 6 | SSOD | SEASHORE MARITIME LIMITED | | | SCAC4 |
| 7 | SSOE | SIX SIX ONE TWO FIVE NINE EIGHT (66 | | | SCAC4 |
| 8 | SSOF | SUNSHINE OIL & FUELS INC | | | SCAC4 |
| 9 | SSOG | SAM & SONS TRUCKING | | | SCAC4 |
| 10 | SSOI | SUN OIL TRUCKING LLC | | | SCAC4 |
| 11 | SSOJ | SEAFOOD SOURCE OF LOUISIANA, THE | | | SCAC4 |
| 12 | SSOK | SANCHE, SORRENTINO | | | SCAC4 |
| 13 | SSOM | STAVANGER BLOSSOM KS | | | SCAC4 |
| 14 | SSOO | SMALL & SMALL OIL CO INC | | | SCAC4 |
| 15 | SSOP | SHORTS OIL COMPANY INC | | | SCAC4 |
| 16 | SSOQ | SECURITY STORAGE & VAN COMPANY OF N | | | SCAC4 |
| 17 | SSOR | Sisseton Southern Ry. Co. | added 1/1988; eliminated 10/1989; 1/1994-7/2005 | | NAKINA |
| 18 | SSOR | Sisseton Southern Ry. Co. | added 1/88; eliminated 10/89; 1/94-7/2000 | | NRHS |
| 19 | SSOR | SISSETON SOUTHERN RAILWAY CO. | | | PWRC |
| 20 | SSOR | Sisseton Southern Railway | | | RSRV |
| 21 | SSOR | SISSETON SOUTHERN RAILWAY CO | | | SCAC4 |
| 22 | SSOS | SWAMP SONG STUDIO | | | SCAC4 |
| 23 | SSOU | SASOL OLEFINS AND SURFACTANTS SOUTH | | | SCAC4 |
| 24 | SSOV | SALVIATI & SANTORI OCEAN INC | | | SCAC4 |
| 25 | SSOW | SECURITY STORAGE COMPANY OF WASHING | | | SCAC4 |
| 26 | SSOX | Sunshine State Oil & Refining Co. | 8/1920-7/1923 | | NAKINA |
| 27 | SSOX | SUNSHINE STATE OIL & REFINING CO. | | | PWRC |
| 28 | SSOX | SSAB Oxelösund | | SE | VKM |
| 29 | SSOY | SUNSHINE OIL COMPANY | | | SCAC4 |
