| 1 | ATO | Air Tonga | | TO | AVCODES |
| 2 | ATO | Airways Flygutbildning AB | Callsign: School Flying, | S | AVCODES |
| 3 | ATOA | ATHINIOTISSA SHIPPING CO LTD | | | SCAC3 |
| 4 | ATOA | ALAN TRANSPORT | | | SCAC4 |
| 5 | ATOB | ALTO BROTHERS TRUCKING INC | | | SCAC3 |
| 6 | ATOB | ALTO BROTHERS TRUCKING INC | | | SCAC4 |
| 7 | ATOC | AUTOMOBILE TRANSPORT COMPANY OF CAL | | | SCAC3 |
| 8 | ATOE | AUTO EXPRESS SALDIVAR | | | SCAC4 |
| 9 | ATOF | AIRFREIGHT TWO ONE ZERO ZERO (2100) | | | SCAC4 |
| 10 | ATOG | ANTON TOUR & TRAVEL SERVICE | | | SCAC3 |
| 11 | ATOH | AUTO HAULERS INC | | | SCAC3 |
| 12 | ATOH | ATOCHA TRUCKING | | | SCAC4 |
| 13 | ATOI | ALTOM TRANSPORT, INC | | | SCAC3 |
| 14 | ATOI | ALTOM TRANSPORT INC | | | SCAC4 |
| 15 | ATOJ | AIRPORT TRANSPORTATION SERVICE | | | SCAC3 |
| 16 | ATOJ | AZTECA TRANSPORT | | | SCAC4 |
| 17 | ATOK | ATOCHEM | | | PWRC |
| 18 | ATOK | ANCO TRANSPORTATION SERIVCE | | | SCAC3 |
| 19 | ATOK | ARTEK MILLWORK | | | SCAC4 |
| 20 | ATOL | AIRLINE TOWING INC | | | SCAC3 |
| 21 | ATOL | ATLANTIC OCEAN LINE LTD | | | SCAC4 |
| 22 | ATOM | ATOMIC TRANSFER LIMITED | | | SCAC3 |
| 23 | ATON | ARMORED TRANSPORT OF NEVADA INC | | | SCAC3 |
| 24 | ATOO | AMERICAN TRANSIT & TOUR | | | SCAC3 |
| 25 | ATOO | ARLEN TOOL CO LTD | | | SCAC4 |
| 26 | ATOP | AMTRAIL TRANSPORTATION INC | | | SCAC3 |
| 27 | ATOP | AUTOTRANSPORTES REFRIGERADOS TORRCO | | | SCAC4 |
| 28 | ATOQ | AMAR TRANSPORTATION INC | | | SCAC3 |
| 29 | ATOR | AUTO MOVERS INC | | | SCAC3 |
| 30 | ATOS | AT-ONCE DELIVERY SYSTEM INCORPORATE | | | SCAC3 |
| 31 | ATOS | ADAMS TRANSPORT COMPANY | | | SCAC4 |
| 32 | ATOT | ATOMIC TRANSIT, INC | | | SCAC3 |
| 33 | ATOT | AIR-TIME ON-TIME EXPRESS | | | SCAC4 |
| 34 | ATOU | ARKEMA | | F | BIC |
| 35 | ATOU | ATOCHEM | | | PWRC |
| 36 | ATOU | Atochem | | | RSRV |
| 37 | ATOU | ATOCHEM | | | SCAC3 |
| 38 | ATOU | ATOFINA | | | SCAC4 |
| 39 | ATOW | ATLAS TOWING CO/CONVENT GARDEN SERV | | | SCAC3 |
| 40 | ATOW | A TOWING SERVICE LTD | | | SCAC4 |
| 41 | ATOY | ANTHONY TRUCK SERVICES | | | SCAC4 |
