| O8 | OHK | Oasis Hong Kong Airlines | |
| OA | OAL | 050 | Olympic Airways |
| OB | ASZ | 562 | Astrakhan Airlines |
| OC | GZP | Gazpromavia Aviation Company | |
| OD | ULA | 822 | Zuliana de Aviacion |
| OG | AGU | 937 | Air Guadaloupe |
| OG | AAT | Austrian Airtransport | |
| OH | COM | 886 | Comair - Delta Connection |
| OK | CSA | 064 | Czech Airlines |
| OL | OLT | 704 | OLT- Ostfriesische Lufttransport GmbH |
| OM | MGL | 289 | MIAT-Mongolian Airlines |
| ON | RON | 123 | Air Nauru |
| OO | SKW | 302 | Sky West Airlines |
| OR | AOR | 687 | Air Comores |
| OR | TFL | 266 | Arkefly |
| OR | CRF | 107 | Crimea Air |
| OS | AUA | 257 | Austrian Cargo |
| OT | VAT | 246 | Avant Airlines |
| OU | CTN | 831 | Croatia Airlines |
| OV | ELL | 960 | Estonian Air |
| OW | OWS | Cargosur | |
| OX | OEA | 578 | Orient Thai Airlines |
| OZ | AAR | 988 | Asiana Airlines |