| 1 | WSX | Wessex Air Services Ltd. | Callsign: Wessex, | GB | AVCODES |
| 2 | WSX | Eurojet Ltd. d/b/a Merlin | Callsign: Wessex, | GB | AVCODES |
| 3 | WSX | Weirton Steel Co. | 8/1920-10/1957; eliminated 7/1959 | | NAKINA |
| 4 | WSX | Weirton Steel Co. Division, National Steel Corp. | added 7/1959; 4/1961 | | NAKINA |
| 5 | WSX | Weirton Steel Division, National Steel Corp. | 7/1965-10/1966 | | NAKINA |
| 6 | WSX | Weirton Steel Co. Division, National Steel Corp. | eliminated 1/1967 | | NAKINA |
| 7 | WSX | Weirton Steel Division, National Steel Corp. | added 1/1967; 4/1970-1/1980; eliminated 5/1983; 1/1994-7/2005 (not listed) | | NAKINA |
| 8 | WSX | Weirton Steel Co. | 4/38-10/57; eliminated 7/59 | | NRHS |
| 9 | WSX | Weirton Steel Co. Division, National Steel Corp. | added 7/59; 4/61 | | NRHS |
| 10 | WSX | Weirton Steel Division, National Steel Corp. | 7/65-10/66 | | NRHS |
| 11 | WSX | Weirton Steel Co. Division, National Steel Corp. | eliminated 1/67 | | NRHS |
| 12 | WSX | Weirton Steel Division, National Steel Corp. | added 1/67; 4/70-1/80; eliminated 5/83; 1/94-7/2000 | | NRHS |
| 13 | WSX | WEIRTON STEEL DIV., NATIONAL STEEL CORP. | | | PWRC |
| 14 | WSX | National Steel Corporation Weirton Steel Division | | | RSRV |
| 15 | WSXC | WILES TRANSPORT INC | | | SCAC4 |
| 16 | WSXD | WESTERN EXPRESS (DEDICATED DIVISION | | | SCAC4 |
| 17 | WSXE | WESTERN EXPRESS (EMERGENCY DIVISION | | | SCAC4 |
| 18 | WSXF | WESTERN EXPRESS (FLATBED DIVISION) | | | SCAC4 |
| 19 | WSXI | WESTERN EXPRESS INC | | | SCAC4 |
| 20 | WSXL | WHITE STAR TRANSPORTATION LLC | | | SCAC4 |
| 21 | WSXR | WESTCO EXPRESS INC | | | SCAC4 |
| 22 | WSXT | WESTERN TRANSPORT LLC | | | SCAC4 |
| 23 | WSXW | WILSONS TRANSIT | | | SCAC4 |
