| 1 | 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 |
| 2 | DH | Discovery Airways | ICAO: DVA, Callsign: Discovery Airways, Ceased operations on 13 July 1990 | USA | AVCODES |
| 3 | DH | Transairco | | F | AVCODES |
| 4 | DH | Independence Air | ICAO: IDE, Callsign: Independence Air, IATA Prefix: 480, Ceased operations on 05 January 2006. Formerly Atlantic Coast Airlines | USA | AVCODES |
| 5 | DH | Sahand Asia Airlines | | IR | AVCODES |
| 6 | DH | Norwegian Air Norway AS | ICAO: NAN, Callsign: Norship, | N | AVCODES |
| 7 | DH | Douniah Airlines | Designator DH recalled by IATA | RMM | AVCODES |
| 8 | DH | Delaware and Hudson Ry. Co., Inc. | added 7/1992; 1/1994-7/2005 | | NAKINA |
| 9 | DH | D & H Corp. | added 7/1991; eliminated 7/1992 | | NAKINA |
| 10 | DH | Delaware and Hudson Ry. Co., Inc. | 1/1975-1/1980; eliminated 7/1991 | | NAKINA |
| 11 | DH | Delaware and Hudson Ry. Co., Inc. | 1/75-1/80; eliminated 7/91 | | NRHS |
| 12 | DH | D & H Corp. | added 7/91; eliminated 7/92 | | NRHS |
| 13 | DH | Delaware and Hudson Ry. Co., Inc. | added 7/92; 1/94-7/2000 | | NRHS |
| 14 | DH | CANADIAN PACIFIC RAILWAY [DELAWARE & HUDSON RAILWAY COMPANY; D & H CORP.] | | | PWRC |
| 15 | DH | Delaware and Hudson Railway | | | RSRV |
| 16 | DH | DELAWARE & HUDSON RAILWAY COMPANY I | | | SCAC4 |
| 17 | DH | Delaware and Hudson Railroad | | USA | TRAFFIC |
| 18 | DH | Dillinger Hüttenwerkwerke AG | | DE | VKM |
| 19 | DHA | Dahla Airlines | | ZRE | AVCODES |
| 20 | DHA | DHL Air (Austria) GmbH | IATA: Q7, Callsign: Yellow Tail, | A | AVCODES |
| 21 | DHA | Dahla Airlines | | | ICAO1 |
| 22 | DHAC | DETROIT HAULING AND LOGISTICS LLC | | | SCAC4 |
| 23 | DHAD | DEMONT, HAROLD | | | SCAC4 |
| 24 | DHAG | DURAY HARVESTING | | | SCAC4 |
| 25 | DHAG | Dillinger Hütte AG | Real: DH | D | TRAFFIC |
| 26 | DHAI | DEN HARTOGH AMERICAS INC. | | | SCAC4 |
| 27 | DHAU | CJSC TMT | | | SCAC4 |
| 28 | DHBO | DUHON BROTHERS OIL CO INC | | | SCAC4 |
| 29 | DHBU | DEN HARTOGH DRY BULK LOGISTICS LTD | | GB | BIC |
| 30 | DHC | De Havilland, Inc. | Callsign: De Havilland, | CDN | AVCODES |
| 31 | DHC | De Havilland Aircraft of Canada Ltd | Callsign: De Havilland, | CDN | AVCODES |
| 32 | DHC | De Havilland | | | ICAO1 |
| 33 | DHC | DONNER-HANNA COKE INC. | | | PWRC |
| 34 | DHCI | D & H CONTRACTING INC | | | SCAC4 |
| 35 | DHCO | DEPENDABLE HEATING & COOLING.LLC | | | SCAC4 |
| 36 | DHCR | D H C TRUCKING INC | | | SCAC4 |
| 37 | DHCU | D H CARGA S A | | YV | BIC |
| 38 | DHDB | DICHELLO DISTRIBUTORS INC | | | SCAC4 |
| 39 | DHDC | DELAWARE-HAITI DEVELOPMENT CORPORAT | | | SCAC4 |
| 40 | DHdJ | Dala - Hälsinglands Järnväg (Orsabanan) | 1902 - 1927 | S | svenska-lok.se |
| 41 | DHDO | New York, Susquehanna and Western Ry. Corp. | eliminated 7/1991 | | NAKINA |
| 42 | DHDO | New York, Susquehanna and Western Ry. Corp. | eliminated 7/91 | | NRHS |
| 43 | DHDO | (NYSW) RETIRED 05-31-91 DMC (345){NEW YORK, SUSQUEHANNA & WESTERN RWY.] | | | PWRC |
| 44 | DHDS | DASH DELIVERY SERVICES | | | SCAC4 |
| 45 | DHDU | DEN HARTOGH GLOBAL BV | | NL | BIC |
| 46 | DHE | DAP Helicopteros Ltda. | Callsign: Helidap, | RCH | AVCODES |
| 47 | DHE | DAP Helicopteros | | | ICAO1 |
| 48 | DHE | Delmenhorst - Harpstedter Eisenbahn GmbH | Delmenhorst | D | privat-bahn.de |
| 49 | DHE | Delmenhorst - Harpstedter Eisenbahn GmbH | | D | TRAFFIC |
| 50 | DHE | Delmenhorst-Harpstedter Eisenbahn | | DE | VKM |
| 51 | DHEC | DELAWARE HUDSON & ERIE CARTAGE INC | | | SCAC4 |
| 52 | DHEER | Detsches Heer | The German Army was formed after the unification of Germany under Prussian leadership in 1871 and dissolved in 1919, after the defeat of the German Empire in World War I. | D | TRAFFIC |
| 53 | DHEF | Delmenhorst-Harpstedter Eisenbahnfeunde e.V. | Delmenhorst | D | privat-bahn.de |
| 54 | DHEF | Delmenhorst-Harpstedter Eisenbahnfreunde e.V | | DE | VKM |
| 55 | DHEI | D H ENTERPRISE INC | | | SCAC4 |
| 56 | DHEP | D & H ENTERPRISES | | | SCAC4 |
| 57 | DHEQ | DOG HOUSE EXPRESS | | | SCAC4 |
| 58 | DHEU | D&H Equipment | | | RSRV |
| 59 | DHFC | DHILLON FREIGHT CARRIER LLC | | | SCAC4 |
| 60 | DHFF | DEHOFF TRUCKING INC | | | SCAC4 |
| 61 | DHFS | DOHLE (IOM) LIMITED | | | SCAC4 |
| 62 | DHGU | DEN HARTOGH GAS LOGISTICS | | NL | BIC |
| 63 | DHGU | DEN HARTOGH GAS LOGISTICS | | | SCAC4 |
| 64 | DHHC | D & H HAULING LLC | | | SCAC4 |
| 65 | DHHL | DOUGHERTY HEAVY HAUL | | | SCAC4 |
| 66 | DHHO | DEL-HOLLOW HOLSTEINS | | | SCAC4 |
| 67 | DHHY | DISCOUNT HEAVY HAUL | | | SCAC4 |
| 68 | DHI | Adam SkyConnection Airlines PT | IATA: KI, Callsign: Adam Sky, AOC suspended on 18 March 2008. | RI | AVCODES |
| 69 | DHI | Adam Air | IATA: KI | | ICAO1 |
| 70 | DHIC | D & H INC | | | SCAC4 |
| 71 | DHIN | DBT | | | SCAC4 |
| 72 | DHIT | DHI TRANSPORT LTD | | | SCAC4 |
| 73 | DHIU | DEN HARTOGH LIQUID LOGISTICS BV | | NL | BIC |
| 74 | DHIU | DEN HARTOGH INTERMODAL BV | | | SCAC4 |
| 75 | DHK | DHL Air Limited | IATA: D0, Callsign: World Express, IATA Prefix: 936, | GB | AVCODES |
| 76 | DHK | DHL Air | | | ICAO1 |
| 77 | DHKG | D & H TRUCKING | | | SCAC4 |
| 78 | DHKL | DATE (HK) LIMITED | | | SCAC4 |
| 79 | DHL | DHL Airways, Inc. | IATA: ER, Callsign: Dahl, IATA Prefix: 423, Name changed to ASTAR Air Cargo | USA | AVCODES |
| 80 | DHL | DHL Airways, Inc. | IATA: DZ, Callsign: Dahl, | USA | AVCODES |
| 81 | DHL | ASTAR Air Cargo, Inc. | IATA: ER, Callsign: Dahl, IATA Prefix: 423, Ceased operations on 01 June 2012. Name changed from DHL Airways, Inc. | USA | AVCODES |
| 82 | DHL | Astar Air Cargo | IATA: ER | | ICAO1 |
| 83 | DHL | DHL (Dalsey, Hillblom and Lynn) International GmbH | | D | TRAFFIC |
| 84 | DHLB | DBE HAULERS LLC | | | SCAC4 |
| 85 | DHLC | DHL AIRWAYS INC | | | SCAC4 |
| 86 | DHLD | D H L INTERNATIONAL EXPRESS LTD | | | SCAC4 |
| 87 | DHLF | DHL GLOBAL FORWARDING (HK) LTD | | | SCAC4 |
| 88 | DHLG | DHL EXPRESS (USA) INC | | | SCAC4 |
| 89 | DHLH | DHL AIR LIMITED | | | SCAC4 |
| 90 | DHLK | D & H LLC | | | SCAC4 |
| 91 | DHLO | DAELIM CORPORATION | | | SCAC4 |
| 92 | DHLP | DUNDERAVE HOLDING LTD | | | SCAC4 |
| 93 | DHLQ | CAHILL CARTAGE CO INC | | | SCAC3 |
| 94 | DHLU | DCM HYUNDAI LTD | | | SCAC4 |
| 95 | DHLV | DAVWOOD HAULING LTD | | | SCAC4 |
| 96 | DHLY | DHL-DANZAS AIR & OCEAN (AGENT FOR A | | | SCAC4 |
| 97 | DHM | Archer Aviation Limited | Callsign: Archer, Ceased operations. | GB | AVCODES |
| 98 | DHM | Archer Aviation | | | ICAO1 |
| 99 | DHME | DURHAM ENTERPRISE INC | | | SCAC4 |
| 100 | DHMI | DAHER MANUFACTURING INC | | | SCAC4 |
