| 1 | MAO | Matair Ltd. | Callsign: Matair, | GB | AVCODES |
| 2 | MAO | Mayo Clinic | Callsign: Mayo, | USA | AVCODES |
| 3 | MAOA | MI ANGELITO BAZAR INFATIL | | | SCAC4 |
| 4 | MAOB | MAAS TRUCKING LLC | | | SCAC4 |
| 5 | MAOC | MARATHON PETROLEUM COMPANY LLC | | | SCAC4 |
| 6 | MAOD | MARCELLO DISTRIBUTORS | | | SCAC4 |
| 7 | MAOE | METRO AUTO EXPRESS LLC | | | SCAC4 |
| 8 | MAOF | MANN ENTERPRISES LLC | | | SCAC4 |
| 9 | MAOG | MANGUM OIL & GAS INC | | | SCAC4 |
| 10 | MAOI | MAGNO INTERNATIONAL LP | | | SCAC4 |
| 11 | MAOL | MAY OIL COM | | | SCAC4 |
| 12 | MAON | MITS AIRCONDITIONING INC | | | SCAC4 |
| 13 | MAOP | MAR-CO CLAY PRODUCTS LTD | | | SCAC4 |
| 14 | MAOR | MARIOS AIR | | | SCAC4 |
| 15 | MAOT | MARTIN BROTHERS TRUCKING INC | | | SCAC4 |
| 16 | MAOV | MID-AMERICA OVERSEAS | | | SCAC1 |
| 17 | MAOV | MID AMERICA OVERSEAS INC | | | SCAC4 |
| 18 | MAOW | MT ALBERTA | | | SCAC4 |
| 19 | MAOY | MARTIN OIL CO INC | | | SCAC4 |
