| 1 | SMX | Alitalia Express | IATA: XM, Callsign: Cee-Cee Express, ICAO callsign changed to Aliexpress | I | AVCODES |
| 2 | SMX | Alitalia Express | IATA: XM, Callsign: Aliexpress, Designator XM recalled by IATA. ICAO callsign changed from Cee-Cee Express | I | AVCODES |
| 3 | SMX | Alitalia Express | IATA: XM, Callsign: Aliexpress, w.e.f. from 13 January 2009 assets transferred to new airline C.A.I. First S.p.A. Designator XM reinstated by IATA. ICAO callsign changed from Cee-Cee Express | I | AVCODES |
| 4 | SMX | C.A.I. First S.p.A. | IATA: XM, w.e.f. 13 January 2009 assets transferred from old airline Alitalia Express. Designator XM reinstated by IATA. ICAO callsign changed from Cee-Cee Express | I | AVCODES |
| 5 | SMX | Swanton Morley (RAF) | Callsign: Swanton, | GB | AVCODES |
| 6 | SMX | Alitalia Express | | | ICAO1 |
| 7 | SMX | Southern Manufacturing Co. | 7/1935; 7/1937 (not listed) | | NAKINA |
| 8 | SMX | Staley Milling Co. | 1/1950-7/1954; eliminated 10/1954 | | NAKINA |
| 9 | SMX | Socony Mobil Oil Co., Inc., Central Region | 10/1957; eliminated 4/1959 | | NAKINA |
| 10 | SMX | Socony Mobil Oil Co., Inc., a Division of Socony Mobil Oil Co., Inc. | added 4/1959; 4/196; eliminated 10/1962 | | NAKINA |
| 11 | SMX | Staley Milling Co. | Jan-52 | | NRHS |
| 12 | SMX | Socony Mobil Oil Co., Inc. | 10/57-4/61 | | NRHS |
| 13 | SMX | *SOUTHERN MANUFACTURING CO. | | | PWRC |
| 14 | SMX | *STALEY MILLING CO. | | | PWRC |
| 15 | SMX | *SOCONY MOBIL OIL CO., INC. | | | PWRC |
| 16 | SMXA | SEMI-EXP | | | SCAC4 |
| 17 | SMXB | SOMNER EXPRESS BROKERAGE INC | | | SCAC4 |
| 18 | SMXE | S AND M TRANSPORTATION INC (BROKERA | | | SCAC4 |
| 19 | SMXF | SIMEX TRANSPORT INC | | | SCAC4 |
| 20 | SMXG | SEMME | | | SCAC4 |
| 21 | SMXH | SIMPLEX LEASING INC | | | SCAC4 |
| 22 | SMXL | SAM-X LOGISTICS LTD | | | SCAC4 |
| 23 | SMXM | SUMM | | | SCAC4 |
| 24 | SMXP | STAR TIME TRANSPORT INC | | | SCAC4 |
| 25 | SMXR | SUAREZ MEXICAN PRODUCTS | | | SCAC4 |
| 26 | SMXT | SAN MIGUELS EXPORTA | | | SCAC4 |
| 27 | SMXV | SEAMLES | | | SCAC4 |
| 28 | SMXW | SEAL TEAM TRANSPORT | | | SCAC4 |
| 29 | SMXY | SMS EXPRESS LLC | | | SCAC4 |
