| 1 | CIO | Il Ciocco International Travel Service Srl | Callsign: Ciocco, Name changed from Il Ciocco | I | AVCODES |
| 2 | CIO | Il Ciocco | Callsign: Ciocco, Name changed to Il Ciocco International Travel Service Srl | I | AVCODES |
| 3 | CIO | Il Ciocco International Travel Service | | | ICAO1 |
| 4 | CIO | CLASSICS LIMOUSINE CO | | | SCAC4 |
| 5 | CIOA | CAMION TRANSPORTATION INC | | | SCAC3 |
| 6 | CIOB | COLONIAL TRANSPORT INC | | | SCAC3 |
| 7 | CIOC | COLLINS OIL CO | | | SCAC3 |
| 8 | CIOD | CITY OF DETROIT | | | SCAC3 |
| 9 | CIOF | CITY OF CHARLOTTE | | | SCAC3 |
| 10 | CIOH | CARETRAN INC | | | SCAC3 |
| 11 | CIOI | CLASSIC COACH INC | | | SCAC3 |
| 12 | CIOL | CONOCO INC | | | SCAC3 |
| 13 | CIOM | CESARIO, M EXCAVATING AND TRUCKING | | | SCAC3 |
| 14 | CION | CITY OF ROME TRANSIT DEPARTMENT | | | SCAC3 |
| 15 | CIOP | CALICO TRANSPORT, INC. | | | SCAC3 |
| 16 | CIOQ | CITY OF DURHAM | | | SCAC3 |
| 17 | CIOR | CITY OF RALEIGH NC | | | SCAC3 |
| 18 | CIOS | CAMIONEROS | | | SCAC3 |
| 19 | CIOT | CONTAINER INNOVATIONS | | | SCAC3 |
| 20 | CIOT | CONTAINER INNOVATIONS | | | SCAC4 |
| 21 | CIOU | CENTRO INTERNAZIONALE STUDI CONTAINERS (C.I.S.CO.) | | I | BIC |
| 22 | CIOV | CIOLFI VAN SERVICE INC | | | SCAC3 |
| 23 | CIOW | CIMA ROAD TOWING | | | SCAC3 |
| 24 | CIOW | CENTRAL IOWA LOGISTICS INC | | | SCAC4 |
| 25 | CIOY | CION BAKERY | | | SCAC4 |
