| 1 | OKA | Okay Airways Company Limited | IATA: BK, Callsign: Okayjet, IATA Prefix: 866, Designator BK* reinstated by IATA | PRC | AVCODES |
| 2 | OKA | Okay Airways | | | ICAO1 |
| 3 | OKAM | OKAMI INC | | | SCAC4 |
| 4 | OKAN | Okanagan Valley Ry. Co. | 7/2000-7/2005 | | NAKINA |
| 5 | OKAN | Okanagan Valley Ry. Co. | Jul-00 | | NRHS |
| 6 | OKAN | OKANAGAN VALLEY RAILWAY (OMNITRAX) | | | PWRC |
| 7 | OKAN | Okanagan Valley Railway (OmniTRAX) | | | RSRV |
| 8 | OKAN | OKANAGAN VALLEY RAILWAY COMPANY | | | SCAC4 |
| 9 | OKAS | OKANOGAN-SEATTLE TRANSPORT COMPANY, | | | SCAC3 |
| 10 | OKAT | OKA TRANSFER CO | | | SCAC3 |
| 11 | OKAT | OKA TRANSFER CO, INC | | | SCAC4 |
| 12 | OKAV | OAKLANE COLONY | | | SCAC4 |
| 13 | OKAYAMA | Okayama Electric Tramway | City: Okayama | J | TRAFFIC |
