| 1 | WCO | Columbia Helicopters, Inc. | Callsign: Columbia Heli, | USA | AVCODES |
| 2 | WCO | Columbia Helicopters | | | ICAO1 |
| 3 | WCOB | WAUNETA COOP OIL COMPANY | | | SCAC4 |
| 4 | WCOC | WARREN COUNTY OIL COOPERATIVE ASSOC | | | SCAC4 |
| 5 | WCOD | WESTERN COMMODITIES | | | SCAC4 |
| 6 | WCOG | WASTELINE CORPORATION | | | SCAC4 |
| 7 | WCOM | WOONSOCKET CONSUMERS COAL CO INC | | | SCAC4 |
| 8 | WCON | WEST CONTRACT SERVICES OF PA | | | SCAC4 |
| 9 | WCOO | WATERLOO CONTAINER | | | SCAC4 |
| 10 | WCOP | WESTERN CO-OP TRANSPORT ASSN | | | SCAC4 |
| 11 | WCOR | Wellsboro & Corning R.R. Co. | added 4/1993; 1/1994-7/2005; eliminated 10/2009 | | NAKINA |
| 12 | WCOR | Wellsboro & Corning R.R. Co. | added 4/93; 1/94-7/2000 | | NRHS |
| 13 | WCOR | WELLSBORO & CORNING RAILROAD COMPANY | | | PWRC |
| 14 | WCOR | Wellsboro and Corning Railroad | | | RSRV |
| 15 | WCOR | WELLSBORO & CORNING RAILROAD | | | SCAC4 |
| 16 | WCOV | WASHINGTON COURIER | | | SCAC4 |
