| Abbreviation | Definition |
|---|---|
| OMSJ | Sharjah International, United Arab Emirat |
| OMY | Phnom Thbeng Meanchey, Cambodia |
| OMZ | Aeropuerto Caracas, Oscar Machado Zuloaga International Airport, Caracas, Venezuela |
| ONB | Ononge, Papua New Guinea |
| OND | Ondangwa, Namibia |
| ONE | Onepusu, Solomon Islands |
| ONG | Mornington Island, Queensland, Australia |
| ONH | Oneonta, New York |
| ONI | Moanamani, Indonesia |
| ONL | O' Neill, Nebraska |
| ONM | Socorro Municipal Airport, Socorro, New Mexico |
| ONN | Onion Bay, Alaska USA |
| ONP | Newport Municipal Airport, Newport, Oregon USA |
| ONR | Monkira, Queensland, Australia |
| ONS | Onslow, Western Australia, Australia |
| ONT | Los Angeles/Ontario International Airport, Ontario, California, USA |
| ONU | Ono-I-Lau, Fiji |
| ONX | Colon, Panama |
| ONY | Olney, Texas USA |
| ONZ | Grosse Ile Municipal Airport, Detroit/Grosse Ile, Michigan USA |