| 1 | OKL | Oklahoma Department of Public Safety, Troop (O) | Callsign: Oklahoma, | USA | AVCODES |
| 2 | OKL | Oklahoma Department of Public Safety | | | ICAO1 |
| 3 | OKLA | OKLAHOMA BORDER EXPRESS INC | | | SCAC3 |
| 4 | OKLA | OAKLIFF TRANSPORTATION | | | SCAC4 |
| 5 | OKLB | OAKLEY, BRUCE INC | | | SCAC3 |
| 6 | OKLB | OAKLEY TRUCKING INC | | | SCAC4 |
| 7 | OKLD | OPTIKINETICS LTD | | | SCAC4 |
| 8 | OKLE | OAKLEY TRANSPORT INC | | | SCAC3 |
| 9 | OKLI | OKLAHOMA LIQUEFIED GAS COMPANY INC | | | SCAC3 |
| 10 | OKLI | O K LOGISTICS INC | | | SCAC4 |
| 11 | OKLR | OAKLEY RELOCATION | | | SCAC4 |
| 12 | OKLT | OAKLEY TRUCKING CO | | | SCAC4 |
| 13 | OKLX | Oklahoma Tank Car Line | 10/1966; eliminated 4/1969 | | NAKINA |
| 14 | OKLX | Oklahoma Tank Car Line | 10/66; eliminated 4/69 | | NRHS |
| 15 | OKLX | OKLAHOMA TANK CAR CO. | | | PWRC |
| 16 | OKLZ | OKLAHOMA FEED | | | PWRC |
