| 1 | OLA | Overland Airways Limited | IATA: OJ, Callsign: Overland, Commenced operations on 26 November 2003. | WAN | AVCODES |
| 2 | OLA | Overland Airways Limited | IATA: OF, Callsign: Overland, Commenced operations on 26 November 2003. IATA designator changed from OJ. | WAN | AVCODES |
| 3 | OLA | Overland Airways | IATA: OJ | | ICAO1 |
| 4 | OLA | Ostseeland Verkehr GmbH | Schwerin (Connex-Gruppe > Veolia Verkehr) | D | privat-bahn.de |
| 5 | OLA | Ostseeland Verkehr GmbH | | DE | VKM |
| 6 | OLAE | OLSEN, ARDEN E | | | SCAC3 |
| 7 | OLAF | OLD SALT FISHING CO LTD | | | SCAC4 |
| 8 | OLAG | OLAUGHLIN, LEO INC | | | SCAC3 |
| 9 | OLAO | OLD ALLEN AUTO SALES | | | SCAC3 |
| 10 | OLAP | OKANOGAN LABEL AND PRINT | | | SCAC4 |
| 11 | OLAT | OLATHE TRUCKING LLC | | | SCAC4 |
| 12 | OLAU | OCCIDENTAL CHEMICAL CORPORATION | | | PWRC |
| 13 | OLAU | Occidental Chemical Corporation | | | RSRV |
| 14 | OLAU | OCCIDENTAL CHEMICAL CORPORATION | | | SCAC3 |
