| 1 | SCH | Schreiner Airways B.V. | IATA: WS, Callsign: Schreiner, Designator WS recalled by IATA | NL | AVCODES |
| 2 | SCH | Schreiner Airways B.V. | IATA: AW, Callsign: Schreiner, IATA Prefix: 405, Designator AW recalled by IATA | NL | AVCODES |
| 3 | SCH | Schreiner Airways B.V. | Callsign: Schreiner, IATA Prefix: 405, The Schreiner Aviation Group was purchased by the CHC Helicopter Corporation in 2005. Designator AW recalled by IATA | NL | AVCODES |
| 4 | SCH | Scenic Air AG | Callsign: Share Plane, | CH | AVCODES |
| 5 | SCH | CHC Airways | IATA: AW | | ICAO1 |
| 6 | SCH | Sägewerk Schwaiger GmbH & Co | | D | TRAFFIC |
| 7 | SCHAU | Ernst Schauffele Schienenverkehrs GmbH & Co KG | Real: ESS | D | TRAFFIC |
| 8 | SCHB | Schöllenenbahn | | CH | TRAFFIC |
| 9 | SCHE | SCHUSTERS EXPRESS INC | | | PWRC |
| 10 | SCHENCK | Schenck Transportation Corp. | | USA | TRAFFIC |
| 11 | SCHENK | Schenk Vins SA | City: Rolle | CH | TRAFFIC |
| 12 | SCHEU | Scheuchzer S.A. | | CH | TRAFFIC |
| 13 | SCHEU | Scheuchzer SA | | CH | VKM |
| 14 | SCHF | SCHEFFLER, J. L | | | SCAC1 |
| 15 | SCHF | SCHEFFLER, J L, TRANSPORT, INC | | | SCAC4 |
| 16 | SCHG | SCHAGRIN GAS COMPANY | | | SCAC4 |
| 17 | SCHH | SCHOEN, ERICH TRUCKING | | | SCAC4 |
| 18 | SCHI | SCHNITZER INDUSTRIES | | | PWRC |
| 19 | SCHJ | SCHUMACHER, ALLEN TRUCKING | | | SCAC4 |
| 20 | SCHK | SCHIEK MOTOR EXPRESS, INC | | | SCAC1 |
| 21 | SCHK | SCHIEK MOTOR EXPRESS, INC | | | SCAC4 |
| 22 | SCHL | SCHROER CORP | | | SCAC4 |
| 23 | SCHM | SINOCHEM SHIPPING CO LTD (HAINAN) | | | SCAC4 |
| 24 | SCHMET | Schmetterling Reise- und Verkehrs-Logistik GmbH | | D | TRAFFIC |
| 25 | SCHMIDTW | Reisebüro Schmidt GmbH | City: Wolfenbüttel | D | TRAFFIC |
| 26 | SCHO | SCHAU, H C & SON INC | | | SCAC4 |
| 27 | SCHON | | City: Schöneiche | D | TRAFFIC |
| 28 | SCHP | SCHIBI TRANSPORTATION LLC | | | SCAC4 |
| 29 | SCHR | SCHOTT TRANSPORTATION INC | | | SCAC4 |
| 30 | SCHS | SCHULTZS MOVING SERVICE | | | SCAC4 |
| 31 | SCHU | SYNTHESIS CHIMICA S.R.L. | | I | BIC |
| 32 | SCHU | SYNTHESIS CHIMICA S R L | | | SCAC4 |
| 33 | SCHUY | Schuylkill Valley Lines | | US-PA | TRAFFIC |
| 34 | SCHV | SCHOONOVER OIL CO INC | | | SCAC4 |
| 35 | SCHW | Schweerbau | | D | TRAFFIC |
| 36 | SCHW | Franz Schwalbe KG (Gleis und Tiefbau -Unternehmen) | | DE | VKM |
| 37 | SCHX | Stauffer Chemical Co., Inc. (Eastern Branch) | 7/1930-7/1954; eliminated 7/1956 | | NAKINA |
| 38 | SCHX | Stauffer Chemical Co. (Eastern Branch) | added 7/1956; 10/1957-1/1980 | | NAKINA |
| 39 | SCHX | Stauffer Chemical Co. | eliminated 4/1990 | | NAKINA |
| 40 | SCHX | Rhone-Poulenc Basic Chemicals Co. | added 4/1990; 1/1994; eliminated 10/1999 | | NAKINA |
| 41 | SCHX | Rhodia, Inc. | added 10/1999; 7/2000; eliminated 4/2004; added 1/2005; 7/2005; eliminated 4/2006 | | NAKINA |
| 42 | SCHX | Innophos, Inc. | added 4/2006; eliminated 4/2008 | | NAKINA |
| 43 | SCHX | Stauffer Chemical Co., Inc. (Eastern Branch) | 4/38-1/52; eliminated 7/56 | | NRHS |
| 44 | SCHX | Stauffer Chemical Co. (Eastern Branch) | added 7/56; 10/57-1/80 | | NRHS |
| 45 | SCHX | Stauffer Chemical Co. | eliminated 4/90 | | NRHS |
| 46 | SCHX | Rhone-Poulenc Basic Chemicals Co. | added 4/90; 1/94; eliminated 10/99 | | NRHS |
| 47 | SCHX | Rhodia, Inc. | added 10/99; 7/2000 | | NRHS |
| 48 | SCHX | INNOPHOS, INC. [RHODIA, INC. ; (RPBX) RHONE-POULENC BASIC CHEMICALS COMPANY; STAUFFER CHEMICAL CO.] | | | PWRC |
| 49 | SCHX | Stauffer Chemical | | | RSRV |
| 50 | SCHZ | RETIRED 05-03-93 ATP | | | PWRC |
