| 1 | SGN | Imperial Air Charter Ltd. | Callsign: Sovereign, | GB | AVCODES |
| 2 | SGN | Siam General Aviation Company Limited d/b/a Nok Mini Airlines | IATA: 5E, Callsign: Siam, Ceased Operations during 2014. | T | AVCODES |
| 3 | SGN | Siam GA | | | ICAO1 |
| 4 | SGND | SMOKING GUN CATTLE CARRIERS LTD | | | SCAC4 |
| 5 | SGNF | SIGNAL TRUCKING LP | | | SCAC4 |
| 6 | SGNG | SIGNATURE | | | SCAC4 |
| 7 | SGNH | SANGAMON TRANSPORTATION GROUP | | | SCAC4 |
| 8 | SGNI | SGS TRANSPORT INC | | | SCAC4 |
| 9 | SGNJ | SYGMA NETWORK, THE | | | SCAC4 |
| 10 | SGNK | SLAGNEB | | | SCAC4 |
| 11 | SGNM | SARGEANT MARINE INC | | | SCAC4 |
| 12 | SGNN | SMITH, GARY N TRUCKING INC | | | SCAC4 |
| 13 | SGNO | SARGENTO TRANPORTATION LLC | | | SCAC4 |
| 14 | SGNP | SIGNATURE TRANSPORT, INC | | | SCAC1 |
| 15 | SGNP | SEGUIN TRANSPORT | | | SCAC4 |
| 16 | SGNS | STURGEON & SON INC | | | SCAC4 |
| 17 | SGNU | SOGIN SPA | | I | BIC |
| 18 | SGNU | SOGIN SPA | | | SCAC4 |
| 19 | SGNV | SEATRADE GROUP N V | | | SCAC4 |
| 20 | SGNW | SCHILLING INC | | | SCAC4 |
| 21 | SGNY | SEA GATE NAVIGATION LTD | | | SCAC4 |
