| 1 | SCO | Helikopterservice AB, Euro Air | IATA: YQ, Callsign: Swedcopter, | S | AVCODES |
| 2 | SCO | Scoot Private Ltd | IATA: OQ, Callsign: Scooter, IATA Prefix: 668, IATA Designator changed to TZ w.e.f. 14 May 2012. | SGP | AVCODES |
| 3 | SCO | Scoot Private Ltd | IATA: TZ, Callsign: Scooter, IATA Prefix: 668, Name changed to Scoot Tigerair Pte. Ltd. (Merged with Tigerair.). IATA Designator changed from OQ w.e.f. 14 May 2012. | SGP | AVCODES |
| 4 | SCO | Air Charter Scotland Europe Ltd. | Callsign: Braveheart, | M | AVCODES |
| 5 | SCO | Helikopterservice Euro Air | | | ICAO1 |
| 6 | SCO | Scoot | | SGP | TRAFFIC |
| 7 | SCOB | SCOTT TRANSPORT | | | SCAC4 |
| 8 | SCOF | SUNCOAST AIR TRANSPORTATION INC | | | SCAC4 |
| 9 | SCOJ | SCOTT TRANSPORT INC | | | SCAC4 |
| 10 | SCOK | SCOTTS TRUCKING LLC | | | SCAC4 |
| 11 | SCOL | SOUTHERN CONSOLIDATED SYSTEMS INC | | | SCAC4 |
| 12 | SCON | Southern Connect | | GB | TRAFFIC |
| 13 | SCOO | SCIOTO OIL CO INC | | | SCAC4 |
| 14 | SCOQ | SCOTT, ROBERT | | | SCAC4 |
| 15 | SCOR | SCHOLL OIL AND TRANSPORTATION CO | | | SCAC4 |
| 16 | SCOS | SEACO AIRLINES INC | | | SCAC4 |
| 17 | SCOT | Abellio ScotRail | | GB | TRAFFIC |
| 18 | SCOU | STAR CONTAINER SERVICES | | | SCAC4 |
| 19 | SCOV | SCOVIL, S E TRUCKING INC | | | SCAC4 |
| 20 | SCOX | The Southern Cotton Oil Co. | 8/1920-7/1923 | | NAKINA |
| 21 | SCOX | The Sco Tank Line, Inc. | 7/1930-1/1946 | | NAKINA |
| 22 | SCOX | Shippers' Car Line Corp. | 4/1947 | | NAKINA |
| 23 | SCOX | Scoular Bishop Grain Co. | added 4/1979; 1/1980; eliminated 7/1985 | | NAKINA |
| 24 | SCOX | Scoular Grain Co. | added 7/1985 | | NAKINA |
| 25 | SCOX | The Scoular Co. | 1/1994; eliminated 10/1999; 7/2000-7/2005 (not listed) | | NAKINA |
| 26 | SCOX | The Sco Tank Line, Inc. | Apr-38 | | NRHS |
| 27 | SCOX | Scoular Bishop Grain Co. | added 4/79; 1/80 | | NRHS |
| 28 | SCOX | The Scoular Co. | 1/94; eliminated 10/99; 7/2000 | | NRHS |
| 29 | SCOX | *SOUTHERN COTTON OIL CO. | | | PWRC |
| 30 | SCOX | *SHIPPERS' CAR LINE, INC. [SCO TANK LINE, INC.] | | | PWRC |
| 31 | SCOX | *SCOULAR CO. [SCOULAR BISHOP GRAIN COMPANY] | | | PWRC |
| 32 | SCOX | Scoular Bishop Grain | | | RSRV |
| 33 | SCOX | SCOULAR COMPANY, THE | | | SCAC4 |
| 34 | SCOX | The Scoular Co. | | USA | TRAFFIC |
| 35 | SCOY | SCOPE TRANSPORTATION | | | SCAC4 |
| 36 | SCOZ | *CRAB ORCHARD & EGYPTIAN RAILROAD | | | PWRC |
| 37 | SCOZ | *SPROUSE CREEK COAL CO. | | | PWRC |
| 38 | SCOZ | Crab Orchard and Egyptian Railroad | | | RSRV |
| 39 | SCOZ | CRAB ORCHARD & EGYPTIAN RAILROAD | | | SCAC4 |
| 40 | SCOZ | Sprouse Creek Coal Company | | USA | TRAFFIC |
