| 1 | MTA | Mitchell Aero, Inc. d/b/a Gak/Mitchell Aero, Inc. | Callsign: Gak Aviation, | USA | AVCODES |
| 2 | MTA | GAK/Mitchell Aero | | | ICAO1 |
| 3 | MTA | METROPOLITAN TRANSPORTATION AUTHORITY (NEW YORK) | | | PWRC |
| 4 | MTA | Metropolitan Transport Authority | City: New York | USA | TRAFFIC |
| 5 | MTAA | MTA TRANSPORTATION INC | | | SCAC4 |
| 6 | MTAB | Malmtrafik AB (Malmbanen) | 1996 - | S | svenska-lok.se |
| 7 | MTAB | Metropolitan Transport Authority Bus Company | | USA | TRAFFIC |
| 8 | MTAB | Malmtrafik i Kiruna AB | | SE | VKM |
| 9 | MTAC | MINATITLAN AL CARMEN RAILROAD | | | PWRC |
| 10 | MTAC | MORGAN LOGISTICS LLC | | | SCAC4 |
| 11 | MTAD | MILLER TRANSFER & STORAGE | | | SCAC4 |
| 12 | MTAF | MATA TRUCKING INC | | | SCAC4 |
| 13 | MTAI | MT TRANSPORTATION SERVICES INC | | | SCAC4 |
| 14 | MTAK | MAICOLC TRANSPORT | | | SCAC4 |
| 15 | MTALIB | MTA Long Island Bus | | USA | TRAFFIC |
| 16 | MTAM | MTB FREIGHTWAYS LTD | | | SCAC4 |
| 17 | MTAP | METAUX PRODUIT DT INC | | | SCAC4 |
| 18 | MTAP | Metropolitan Toronto Auxiliary Police | | CDN | TRAFFIC |
| 19 | MTAS | METRO ATLANTA EXPRESS | | | SCAC4 |
| 20 | MTAS | | | N | TRAFFIC |
| 21 | MTAS | Malmtrafik A/S | | NO | VKM |
| 22 | MTAU | FINEBRO 3 S.L. | | E | BIC |
| 23 | MTAW | MONROE TRACTOR AND IMPLEMENT CO INC | | | SCAC4 |
| 24 | MTAX | MTAX Corp. | added 7/1988; 1/1994; eliminated 4/1996; 7/2000-7/2005 (not listed) | | NAKINA |
| 25 | MTAX | MTAX Corp. | added 7/88; 1/94; eliminated 4/96; 7/2000 | | NRHS |
| 26 | MTAX | *MASS TRANSIT ADMINISTRATION | | | PWRC |
| 27 | MTAX | +MTAX CORPORATION | | | PWRC |
| 28 | MTAX | MTAX Corporation | | | RSRV |
| 29 | MTAY | M TRANSPORT | | | SCAC4 |
