| 1 | AOK | Aeroatlantico Colombia | | | ICAO1 |
| 2 | AOK | Arkansas-Oklahoma R.R., Inc. | added 7/1996; 7/2000-7/2005; eliminated 7/2005; added 1/2006 | | NAKINA |
| 3 | AOK | Arkansas-Oklahoma R.R., Inc. | added 7/96; 7/2000 | | NRHS |
| 4 | AOK | ARKANSAS-OKLAHOMA RR | | | PWRC |
| 5 | AOK | Arkansas-Oklahoma Railroad | | | RSRV |
| 6 | AOK | ARKANSAS-OKLAHOMA RAILROAD INC | | | SCAC4 |
| 7 | AOK | Arkansas-Oklahoma | | USA | TRAFFIC |
| 8 | AOKA | A-OK AIR FREIGHT | | | SCAC3 |
| 9 | AOKA | A-ONE (A-1) KITCHENS BY SIERRA INC | | | SCAC4 |
| 10 | AOKB | A-ONE (A-1) TRUCKING | | | SCAC4 |
| 11 | AOKC | ARGO TRUCKING CORP | | | SCAC4 |
| 12 | AOKD | A-ONE (A-1) TRUCK LINE | | | SCAC4 |
| 13 | AOKF | A-OKAY FORWARDERS | | | SCAC3 |
| 14 | AOKG | AOK TRUCKING INC | | | SCAC4 |
| 15 | AOKI | ABCO TRUCKING INC | | | SCAC4 |
| 16 | AOKL | ACME TRUCK LINE OF OKLAHOMA INC | | | SCAC3 |
| 17 | AOKL | ARMSTRONG RELOCATION OKLAHOMA CITY | | | SCAC4 |
| 18 | AOKM | A OKAY MOVING & STORAGE | | | SCAC4 |
| 19 | AOKO | A-OK MOVING & STORAGE | | | SCAC3 |
| 20 | AOKO | A-OK MOVING & STORAGE | | | SCAC4 |
| 21 | AOKP | A OK TRANSPORTATION INC | | | SCAC4 |
| 22 | AOKS | A O K SHUTTLE SERVICE INC | | | SCAC3 |
| 23 | AOKT | AOK TRUCKING | | | SCAC3 |
| 24 | AOKT | AOK TRUCKING | | | SCAC4 |
| 25 | AOKW | AOK TOWING INC | | | SCAC3 |
| 26 | AOKX | Greenbrier Management Services, LLC | added 1/2010 | | NAKINA |
| 27 | AOKX | GREENBRIER MANAGEMENT SERVICES LLC | | | SCAC4 |
