| 1 | SMI | Aero Sami, S.A. de C.V. | Callsign: Sami, | MEX | AVCODES |
| 2 | SMI | Altair Linee Aeree S.p.A. | IATA: SM, Callsign: Sierra Mike, Ceased Operations | I | AVCODES |
| 3 | SMI | Aero Sami | | | ICAO1 |
| 4 | SMI | STATE OF MICHIGAN | | | PWRC |
| 5 | SMIA | SMITH, ARCHIE TRUCKING | | | SCAC4 |
| 6 | SMIC | SMITH OIL CO | | | SCAC4 |
| 7 | SMID | SMITH, DEAN | | | SCAC4 |
| 8 | SMIF | SEMILLAS Y FORRAJES EL RUBI SA DE | | | SCAC4 |
| 9 | SMIH | SMITH TRUCK BROKERS INC | | | SCAC4 |
| 10 | SMII | SUMMER MARITIME S A | | | SCAC4 |
| 11 | SMIL | STENA METAL INTERNATIONAL | | | SCAC4 |
| 12 | SMIM | SMART INTERMODAL LLC | | | SCAC4 |
| 13 | SMIN | SIMIONE OIL CO INC | | | SCAC4 |
| 14 | SMIR | SMITH, K TRUCKING INC | | | SCAC4 |
| 15 | SMIT | SMITH, T D | | | SCAC4 |
| 16 | SMIU | SMI-ASL | | | SCAC4 |
| 17 | SMIX | Schreiber Mills, Inc. | added 7/1959; 4/1961-1/1975; eliminated 7/1976 | | NAKINA |
| 18 | SMIX | Structural Metals, Inc. | added 1/1986; 1/1994-7/2005 | | NAKINA |
| 19 | SMIX | Schreiber Mills, Inc. | added 7/59; 4/61-1/75; eliminated 7/76 | | NRHS |
| 20 | SMIX | Structural Metals, Inc. | added 1/86; 1/94-7/2000 | | NRHS |
| 21 | SMIX | *SCHREIBER MILLS, INC. | | | PWRC |
| 22 | SMIX | +STRUCTURAL METALS, INC. | | | PWRC |
| 23 | SMIX | Structural Metals | | | RSRV |
| 24 | SMIX | STRUCTURAL METALS INC | | | SCAC4 |
| 25 | SMIY | SMITH MARITIME INC | | | SCAC4 |
