| 2001 | DGNO | DALLAS GARLAND & NORTHEASTERN RAILR | | | SCAC4 |
| 2002 | DGNO | Dallas, Garland & Northeastern R.R., Inc. | | USA | TRAFFIC |
| 2003 | DGNR | DIGGINS AND ROSE INC | | | SCAC4 |
| 2004 | DGNS | DRAGON STAR INC | | | SCAC4 |
| 2005 | DGNV | DIGREGORIO NAVEGACAS | | | SCAC1 |
| 2006 | DGNV | DG & V REIMER | | | SCAC4 |
| 2007 | DGO | Dgo Jet. S.A. de C.V. | Callsign: Dgo jet, | MEX | AVCODES |
| 2008 | DGO | DGO Jet | | | ICAO1 |
| 2009 | DGOR | DURANGO TRANSPORT | | | SCAC4 |
| 2010 | DGOT | DURANGO TRANSPORT | | | SCAC4 |
| 2011 | DGP | Cuerpo Nacional de Policia | | E | AVCODES |
| 2012 | DGPC | DOUGLAS, PAUL TRANSPORT INC | | | SCAC4 |
| 2013 | DGPN | DEL GROSSO PACKING COMPANY INC | | | SCAC4 |
| 2014 | DGPO | DIMETRI GARDIKAS PRODUCE CO INC | | | SCAC4 |
| 2015 | DGPS | DEGROATE PETROLEUM SERVICE INC | | | SCAC4 |
| 2016 | DGRG | D G RIGGING INC | | | SCAC4 |
| 2017 | DGRL | DELGADO GARZA, RAUL | | | SCAC4 |
| 2018 | DGRP | DUNTON GROUP | | | SCAC4 |
| 2019 | DGRR | DOS GRINGOS | | | SCAC4 |
| 2020 | DGRT | DANIELS, G R TRUCKING INC | | | SCAC4 |
| 2021 | DGSB | DANIELS, GRAY STABLE | | | SCAC4 |
| 2022 | DGSC | DGS OCEAN | | | SCAC4 |
| 2023 | DGSD | DMODOM GRADING SERVICE | | | SCAC4 |
| 2024 | DGSO | DOUGLAS OIL CO INC | | | SCAC4 |
| 2025 | DGSQ | DAYSTAR GLOBAL SOLUTIONS INC | | | SCAC4 |
| 2026 | DGSS | DONGSUE SHIPPING CO LTD | | | SCAC4 |
| 2027 | DGST | DOUGS TRUCKING INC | | | SCAC4 |
| 2028 | DGSU | DUBAI GENERAL SHIPPING SERVICES LLC | | | SCAC4 |
| 2029 | DGSV | D & G SERVICES LLC | | | SCAC4 |
| 2030 | DGT | Digital Equipment Corporation | Callsign: Digital, | USA | AVCODES |
| 2031 | DGT | Digital Equipment Corporation | | | ICAO1 |
| 2032 | DGT | Deutsche Gleis- und Tiefbau GmbH | Berlin | D | privat-bahn.de |
| 2033 | DGT | Deutsche Gleis und Tiefbau | | D | TRAFFIC |
| 2034 | DGT | Deutsche Gleis- und Tiefbau | | DE | VKM |
| 2035 | DGTB | DG TRANSFER LLC | | | SCAC4 |
| 2036 | DGTD | DG TRANSPORT LLC | | | SCAC4 |
| 2037 | DGTE | DOUBLE G TRANSPORT | | | SCAC4 |
| 2038 | DGTF | DIAMOND G TRANSFER | | | SCAC4 |
| 2039 | DGTG | DONGTING EXPRESS USA INC | | | SCAC4 |
| 2040 | DGTH | D & G TRUCKING | | | SCAC4 |
| 2041 | DGTJ | DE GROAT TRANSPORTATION | | | SCAC4 |
| 2042 | DGTK | D & G TRUCKING | | | SCAC4 |
| 2043 | DGTQ | DGT LLC | | | SCAC4 |
| 2044 | DGTR | DEE GEE TRUCKING LLC | | | SCAC4 |
| 2045 | DGTT | DOUBLE G TRANSPORT LLC | | | SCAC4 |
| 2046 | DGTW | D & G TRANSPORT | | | SCAC4 |
| 2047 | DGU | Deutsche Gleisbau Union GmbH & Co. KG | | DE | VKM |
| 2048 | DGUK | D G TRUCKING & EQUIPMENT SALES | | | SCAC4 |
| 2049 | DGUS | DEGUST MER INC | | | SCAC4 |
| 2050 | DGV | Smart Airlines LLC | Callsign: Smart Airlines, Planned start-up. | AM | AVCODES |
| 2051 | DGV | DORCHESTER GRAIN | | | PWRC |
| 2052 | DGVR | DURBIN & GREENBRIER VALLEY RAILROAD INC. | | | PWRC |
| 2053 | DGVR | Durbin and Greenbrier Valley Railroad | | | RSRV |
| 2054 | DGVR | DURBIN & GREENBRIER VALLEY RAILROAD | | | SCAC4 |
| 2055 | DGVX | DURBIN & GREENBRIER VALLEY SCENIC RAILROAD | | | PWRC |
| 2056 | DGWT | DOGWOOD TRANSPORT LTD | | | SCAC4 |
| 2057 | DGX | Dasnair SA | Callsign: Dasna, | CH | AVCODES |
| 2058 | DGX | Dasnair | | | ICAO1 |
| 2059 | DGXN | DGX | | | SCAC4 |
| 2060 | DGXP | DRAGON EXPRESS INC | | | SCAC4 |
| 2061 | DGXS | D G EXPRESS | | | SCAC4 |
| 2062 | DGXT | DINGUS TRANSPORT | | | SCAC4 |
| 2063 | DGXV | DIGITAL TRANSPORTATION SERVICES | | | SCAC4 |
| 2064 | DGZM | DIEGUEZ MARTIN, CASTRO | | | SCAC4 |
| 2065 | DGZU | DAĞGAZ | | TR | BIC |
| 2066 | DH | Atlantic Coast Airlines d/b/a United Express | ICAO: BLR, Callsign: Blue Ridge, IATA Prefix: 480, Name changed to Independence Air w.e.f. 05 January 2006. | USA | AVCODES |
| 2067 | DH | Discovery Airways | ICAO: DVA, Callsign: Discovery Airways, Ceased operations on 13 July 1990 | USA | AVCODES |
| 2068 | DH | Transairco | | F | AVCODES |
| 2069 | DH | Independence Air | ICAO: IDE, Callsign: Independence Air, IATA Prefix: 480, Ceased operations on 05 January 2006. Formerly Atlantic Coast Airlines | USA | AVCODES |
| 2070 | DH | Sahand Asia Airlines | | IR | AVCODES |
| 2071 | DH | Norwegian Air Norway AS | ICAO: NAN, Callsign: Norship, | N | AVCODES |
| 2072 | DH | Douniah Airlines | Designator DH recalled by IATA | RMM | AVCODES |
| 2073 | DH | Delaware and Hudson Ry. Co., Inc. | added 7/1992; 1/1994-7/2005 | | NAKINA |
| 2074 | DH | D & H Corp. | added 7/1991; eliminated 7/1992 | | NAKINA |
| 2075 | DH | Delaware and Hudson Ry. Co., Inc. | 1/1975-1/1980; eliminated 7/1991 | | NAKINA |
| 2076 | DH | Delaware and Hudson Ry. Co., Inc. | 1/75-1/80; eliminated 7/91 | | NRHS |
| 2077 | DH | D & H Corp. | added 7/91; eliminated 7/92 | | NRHS |
| 2078 | DH | Delaware and Hudson Ry. Co., Inc. | added 7/92; 1/94-7/2000 | | NRHS |
| 2079 | DH | CANADIAN PACIFIC RAILWAY [DELAWARE & HUDSON RAILWAY COMPANY; D & H CORP.] | | | PWRC |
| 2080 | DH | Delaware and Hudson Railway | | | RSRV |
| 2081 | DH | DELAWARE & HUDSON RAILWAY COMPANY I | | | SCAC4 |
| 2082 | DH | Delaware and Hudson Railroad | | USA | TRAFFIC |
| 2083 | DH | Dillinger Hüttenwerkwerke AG | | DE | VKM |
| 2084 | DHA | Dahla Airlines | | ZRE | AVCODES |
| 2085 | DHA | DHL Air (Austria) GmbH | IATA: Q7, Callsign: Yellow Tail, | A | AVCODES |
| 2086 | DHA | Dahla Airlines | | | ICAO1 |
| 2087 | DHAC | DETROIT HAULING AND LOGISTICS LLC | | | SCAC4 |
| 2088 | DHAD | DEMONT, HAROLD | | | SCAC4 |
| 2089 | DHAG | DURAY HARVESTING | | | SCAC4 |
| 2090 | DHAG | Dillinger Hütte AG | Real: DH | D | TRAFFIC |
| 2091 | DHAI | DEN HARTOGH AMERICAS INC. | | | SCAC4 |
| 2092 | DHAU | CJSC TMT | | | SCAC4 |
| 2093 | DHBO | DUHON BROTHERS OIL CO INC | | | SCAC4 |
| 2094 | DHBU | DEN HARTOGH DRY BULK LOGISTICS LTD | | GB | BIC |
| 2095 | DHC | De Havilland, Inc. | Callsign: De Havilland, | CDN | AVCODES |
| 2096 | DHC | De Havilland Aircraft of Canada Ltd | Callsign: De Havilland, | CDN | AVCODES |
| 2097 | DHC | De Havilland | | | ICAO1 |
| 2098 | DHC | DONNER-HANNA COKE INC. | | | PWRC |
| 2099 | DHCI | D & H CONTRACTING INC | | | SCAC4 |
| 2100 | DHCO | DEPENDABLE HEATING & COOLING.LLC | | | SCAC4 |
