| 1 | ACR | ASA, Air Starline AG | Callsign: Aircruise, | CH | AVCODES |
| 2 | ACR | Aerocenter, Escuela de Formacion de Pilotos Privados de Avion | Callsign: Aerocenter, | E | AVCODES |
| 3 | ACR | Air Caravane, Inc. | Callsign: Caravane, | CDN | AVCODES |
| 4 | ACR | Aerocenter, Escuela de Formacion de Pioltos Privad | | | ICAO1 |
| 5 | ACR | ALGOMA CENTRAL RAILWAY | | | PWRC |
| 6 | ACRA | ACERRA, RICHARD INC | | | SCAC3 |
| 7 | ACRA | ACERRA TRANSPORTATION GROUP INC | | | SCAC4 |
| 8 | ACRB | AMERICAN CARRIERS INC | | | SCAC3 |
| 9 | ACRB | AMERICAN CARRIERS INC | | | SCAC4 |
| 10 | ACRC | Andalusia & Conecuh R.R. Co., Inc. | added 7/1983; 1/1985; eliminated 10/1990; 1/1994 | | NAKINA |
| 11 | ACRC | Andalusia & Conecuh R.R. Co., Inc. | eliminated 10/90; 1/94 | | NRHS |
| 12 | ACRC | ANDALUSA & CONECUH RAILROAD CO. | | | PWRC |
| 13 | ACRC | Andalusia and Conecuh Railroad | | | RSRV |
| 14 | ACRD | ACORN DELIVERY SERVICE INC | | | SCAC3 |
| 15 | ACRF | ALL CRANE RENTAL OF GEORGIA INC | | | SCAC4 |
| 16 | ACRH | ACTIVE CARHAUL LLC | | | SCAC4 |
| 17 | ACRI | ACRON TRANSPORTATION INC | | | SCAC3 |
| 18 | ACRJ | AL-CAR TRANSPORTERS INC | | | SCAC3 |
| 19 | ACRJ | ACTION COURIERS INC | | | SCAC4 |
| 20 | ACRL | AMERICAN CENTRAL TRANSPORT INC | | | SCAC3 |
| 21 | ACRL | AMERICAN CENTRAL TRANSPORT INC | | | SCAC4 |
| 22 | ACRM | ALS CARTAGE | | | SCAC3 |
| 23 | ACRM | AMARO CAZAREZ, ISMAEL | | | SCAC4 |
| 24 | ACRN | ACORN PIPELINE COMPANY | | | SCAC3 |
| 25 | ACRO | ACORN TRANSPORTATION, INC | | | SCAC3 |
| 26 | ACRP | ACE TRUCK RENTAL CORP | | | SCAC3 |
| 27 | ACRP | ARCON METAL PROCESSING | | | SCAC4 |
| 28 | ACRQ | A C TRANSPORT INC | | | SCAC3 |
| 29 | ACRQ | AMES CONSTRUCTION INC | | | SCAC4 |
| 30 | ACRR | ALLEGANY CENTRAL RAILROAD | | | PWRC |
| 31 | ACRR | ACERET TRUCKING | | | SCAC3 |
| 32 | ACRS | A B INC | | | SCAC4 |
| 33 | ACRT | AMERICAN TRANSPORTERS | | | SCAC3 |
| 34 | ACRU | ACCIPITER OILFIELD EQUIPMENT | | PRC | BIC |
| 35 | ACRV | ACCESS DELIVERY SERVICE | | | SCAC3 |
| 36 | ACRW | ABC CARRIERS INC | | | SCAC3 |
| 37 | ACRX | Elementis Chromium, LP | added 10/2003; 7/2005 | | NAKINA |
| 38 | ACRX | American Chrome & Chemicals Inc. | added 4/1980; 1/1985-1/1994; eliminated 7/1998; 7/2000 (not listed) | | NAKINA |
| 39 | ACRX | American Chrome & Chemicals Inc. | added 4/80; 1/94; eliminated 7/98; 7/2000 | | NRHS |
| 40 | ACRX | ELEMENTIS CHROMIUM LP [AMERICAN CHROME & CHEMICALS INC.] | | | PWRC |
| 41 | ACRX | American Chrome and Chemicals (Elementis Chromium) | | | RSRV |
| 42 | ACRX | ELEMENTIS CHROMIUM LP | | | SCAC4 |
| 43 | ACRY | ARKANSAS CENTRAL RAILWAY CO. | | | PWRC |
| 44 | ACRY | ACCORD MOVING & STORAGE COMPANY | | | SCAC3 |
