| 1 | OJ | Overland Airways Limited | ICAO: OLA, Callsign: Overland, Commenced operations on 26 November 2003. | WAN | AVCODES |
| 2 | OJ | Maof Airlines | | IL | AVCODES |
| 3 | OJ | Fly Jamaica Airways Limited | ICAO: FJM, Callsign: Greenheart, Founded in 2012, Commenced operations on 14 February 2013. Ceased operations on 31 March 2019. | JA | AVCODES |
| 4 | OJ | Nyxair OU | ICAO: NYX, Callsign: Nyx Air, | EST | AVCODES |
| 5 | OJA | Oriental Pearl Airways Ltd. | Callsign: Pearl, | GB | AVCODES |
| 6 | OJAI | OJAI VAN LINES, INC | | | SCAC3 |
| 7 | OJAM | OBERGFELL, JAMES | | | SCAC4 |
| 8 | OJAS | ORTIZ, J A & SONS | | | SCAC4 |
| 9 | OJAV | OTERO, JAVIER | | | SCAC4 |
| 10 | OJCG | ORNELAS, JC TRUCKING | | | SCAC4 |
| 11 | OJCK | O J C TRUCKING INC | | | SCAC3 |
| 12 | OJCT | O. J. - COMMERCIAL TRANSPORT, INC | | | SCAC3 |
| 13 | OJCT | OJC TRUCKING INC | | | SCAC4 |
| 14 | OJES | O'CONNOR, JOHN E & SONS | | | SCAC3 |
| 15 | OJET | OWENS, JAMES E TRUCKING INC | | | SCAC3 |
| 16 | OJF | Occitania Jet Fleet | Callsign: Occitania, Ceased operations. | F | AVCODES |
| 17 | OJF | Orsa Jernvägsförening | | SE | VKM |
| 18 | OJFT | OCONNOR, JOHN F TRUCKING CO | | | SCAC3 |
| 19 | OJGK | ODHAM, JOHN G TRUCKING | | | SCAC4 |
| 20 | OJGR | OLDCASTLE/JOLLY GARDENER | | | SCAC4 |
| 21 | OJGX | Oscar J. Glover | 1/1994-7/2005 (not listed) | | NAKINA |
| 22 | OJGX | Oscar J. Glover | 1/94-7/2000 | | NRHS |
| 23 | OJGX | OSCAR J. GLOVER | | | PWRC |
| 24 | OJGX | Oscar J. Glover | | | RSRV |
| 25 | OJGX | OSCAR J. GLOVER | | | SCAC4 |
| 26 | OJIN | OJINAGA ROMU S DE R L DE C V (MX-33 | | | SCAC4 |
| 27 | OJJ | Østjydske Jernbane | Real: ØJJ, 1876 - 1881 | DK | TRAFFIC |
| 28 | OJLT | OLIVER, J L TRUCKING | | | SCAC4 |
| 29 | OJML | OSORIO, JESUS MANUEL | | | SCAC4 |
| 30 | OJO | OneJetOne Airways | Callsign: Ohjoh, Operations nevere started. | EAK | AVCODES |
| 31 | OJON | O JOHNNY | | | SCAC4 |
| 32 | OJS | Museiföreningen Örnsköldsviks JärnvägsSällskap | | SE | VKM |
| 33 | OJT | Oryx Jet Ltd | Callsign: Orystar, | GB | AVCODES |
| 34 | OJTG | O J TRUCKING INC | | | SCAC3 |
| 35 | OJTI | OLE JAYS TRUCKING INC | | | SCAC3 |
| 36 | OJTP | O-J TRANSPORT COMPANY | | | SCAC3 |
| 37 | OJTX | Tauber Transportation Co. | added 7/1978; 1/1980; eliminated 7/1984; 1/1994 (not listed) | | NAKINA |
| 38 | OJTX | O.J. Tauber | added 7/1957; 10/1957-7/1965; eliminated 10/1965 | | NAKINA |
| 39 | OJTX | O.J. Tauber | 10/57-7/65; eliminated 10/65 | | NRHS |
| 40 | OJTX | Tauber Transportation Co. | added 7/78; 1/80; eliminated 7/84; 1/94 | | NRHS |
| 41 | OJTX | TAUBER TRANSPORTATION CO. [O. J. TAUBER] | | | PWRC |
| 42 | OJTX | Tauber Transportation | | | RSRV |
| 43 | OJVN | O J VENTURES LTD | | | SCAC4 |
| 44 | OJY | Florida Air, Inc. | Callsign: Ohjay, | USA | AVCODES |
| 45 | OJY | Florida Air | | | ICAO1 |
