| Abbreviation | Definition |
|---|---|
| ANS | NAS Transition Implementation Service |
| ANT | Alternative Needs Transportation |
| ANT | Autonomous Navigation Technology |
| ANW | Program Director for Weather and Flight Service Stations |
| AO | Air Observer |
| AO | All Off |
| AO | Aviation Officer |
| AOA | Air Operations Area |
| AOA | Angle Of Attack |
| AOA | Any One Accident |
| AOC | Aeronautical Operational Control |
| AOC | Air Operations Center |
| AOC | Air Operator's Certificate |
| AOCM | Aircraft Out of Commission for Parts |
| AOD | Automatic OverDrive |
| AODB | Airport Operational DataBase |
| AOPA | Aircraft Owners and Pilots Association |
| AOR | Operations Research Service |
| AORS | Association of Ontario Road Supervisors |
| AOT | Agency of Transportation |