| 1 | SKR | Shonkar | Callsign: Shonkar, | RUS | AVCODES |
| 2 | SKR | Skyscapes Air Charters | Callsign: Skyscapes, | ZA | AVCODES |
| 3 | SKR | Skyscapes Air Charters | | | ICAO1 |
| 4 | SKR | Shigaraki Kogen Railway | | J | TRAFFIC |
| 5 | SKRA | SCHRADER, KEN RACING INC | | | SCAC4 |
| 6 | SKRC | S K TRANSPORT INC | | | SCAC4 |
| 7 | SKRD | SPEEDWORK | | | SCAC4 |
| 8 | SKRI | SKRETTING (EAST COAST) | | | SCAC4 |
| 9 | SKRJ | Silkeborg - Kjellerup - Rødkærsbro Jernbane (Kjellerupbanen) | 1924 - 1968 | DK | jernbanen.dk |
| 10 | SKRJ | SILK ROAD SOUTH | | | SCAC4 |
| 11 | SKRJ | Silkeborg - Kjellerup - Rødkærsbro Jernbane (Kjellerupbanen) | | DK | TRAFFIC |
| 12 | SKRL | S & K TRUCKING LTD | | | SCAC4 |
| 13 | SKRM | S K R MOVING INC | | | SCAC4 |
| 14 | SKRO | SILK ROAD TRANSPORT INC | | | SCAC4 |
| 15 | SKRR | SNEAD, K R TRUCKING INC | | | SCAC4 |
| 16 | SKRS | SKEETER TRUCKING | | | SCAC4 |
| 17 | SKRU | SINOKOR MERCHANT MARINE CORP | | ROK | BIC |
| 18 | SKRU | SINOKOR MERCHANT MARINE CO LTD | | | SCAC4 |
| 19 | SKRW | SKUROW BROTHERS OIL COMPANY | | | SCAC4 |
| 20 | SKRX | Skinner Refrigerator Lines | 8/1920 | | NAKINA |
| 21 | SKRX | Schuylkill Railcar L.P. | added 10/1998; eliminated 7/2000; 7/2000-7/2005 (not listed) | | NAKINA |
| 22 | SKRX | Schuylkill Railcar L.P. | added 10/98; 7/2000; eliminated 7/2000 | | NRHS |
| 23 | SKRX | *SKINNER REFRIGERATOR LINES | | | PWRC |
| 24 | SKRX | +SCHUYLKILL RAILCAR L.P. | | | PWRC |
| 25 | SKRX | Schuylkill Railcar | | | RSRV |
| 26 | SKRX | SCHUYLKILL RAILCAR LP | | | SCAC4 |
| 27 | SKRZ | (XTRZ) XTRA INTERMODAL | | | PWRC |
| 28 | SKRZ | XTRA Intermodal | | | RSRV |
| 29 | SKRZ | XTRA INTERMODAL | | | SCAC4 |
