| 1 | DD | Atlantic Coast Jet, Inc. | ICAO: PRT, Callsign: Patriot, IATA Prefix: 949, IATA designator changed to DD | USA | AVCODES |
| 2 | DD | Aerolyon | ICAO: AEY, IATA designator changed to 4Q | F | AVCODES |
| 3 | DD | Contiflug GmbH | | D | AVCODES |
| 4 | DD | Amber Airways | ICAO: ABM, | GB | AVCODES |
| 5 | DD | Georgian Bay Airways Limited | | CDN | AVCODES |
| 6 | DD | Bayu Indonesia Air P.T. | ICAO: BYU, Callsign: Bayu, Designator DD recalled by IATA | RI | AVCODES |
| 7 | DD | Atlantic Coast Jet, Inc. | ICAO: PRT, Callsign: Patriot, IATA Prefix: 949, Desigantor DD recalled by IATA. IATA designator changed from DD* | USA | AVCODES |
| 8 | DD | Sky Asia Co. Ltd. d/b/a Nok Air | ICAO: NOK, Name changed to Nok Airlines Co., Ltd. w.e.f. 18 January 2013 | T | AVCODES |
| 9 | DD | Nok Airlines Company Limited | ICAO: NOK, Callsign: Nok Air, Sky Asia Co. Ltd. d/b/a Nok Air w.e.f. 16 Janaury 2006. Name changed to Nok Airlines Public Co., Ltd. d/b/a Nok Air w.e.f. 18 January 2013. | T | AVCODES |
| 10 | DD | Nok Airlines Public Co., Ltd. d/b/a Nok Air | ICAO: NOK, Callsign: Nok Air, Filed for bankruptcy on 30 July 2020. Name changed from Nok Airlines Company Limited w.e.f. 18 January 2013 | T | AVCODES |
| 11 | DD | D&D Eisenbahngesellschaft mbH | | D | TRAFFIC |
| 12 | DDA | D & D Aviaion | Callsign: Dusty, | USA | AVCODES |
| 13 | DDA | D & D Aviation | | | ICAO1 |
| 14 | DDAB | DAVIDSON, DOUG TRUCKING LLC | | | SCAC4 |
| 15 | DDAD | D & D TRUCKING | | | SCAC4 |
| 16 | DDAG | DHL GLOBAL | | | SCAC4 |
| 17 | DDAH | DH-DHEKELIA SHIPMANAGEME | | | SCAC4 |
| 18 | DDAK | D & D TRUCKING INC | | | SCAC4 |
| 19 | DDAL | DOCKENDALE SHIPPING COMPANY LTD | | | SCAC4 |
| 20 | DDAM | DOUBLE DIAMOND TRANSPORT INC | | | SCAC4 |
| 21 | DDAN | DUTTON, DAN RHONDA | | | SCAC4 |
| 22 | DDAO | D & D TALBOT INC | | | SCAC4 |
| 23 | DDAR | DANS DAIRY LLC | | | SCAC4 |
| 24 | DDAW | DAWNS DAWGS | | | SCAC4 |
| 25 | DDBA | D & D BROKERAGE | | | SCAC4 |
| 26 | DDBB | DANIELS, DALE B | | | SCAC4 |
| 27 | DDBE | D D B ENTERPRISES | | | SCAC4 |
| 28 | DDBP | DIRECT DISTRIBUTION & TRANSPORTATIO | | | SCAC4 |
| 29 | DDBT | D D B TRANSPORT INC | | | SCAC4 |
| 30 | DDCC | D D C LLC | | | SCAC4 |
| 31 | DDCE | DOUGLASS DISTRIBUTING CARRIERS INC | | | SCAC4 |
| 32 | DDCJ | D & D CARRIERS LLC | | | SCAC4 |
| 33 | DDCM | DIRECT DRIVE COURIER/EXPEDITE INC | | | SCAC4 |
| 34 | DDCO | DOUGS RECREATION CENTER LTD | | | SCAC4 |
| 35 | DDCS | DEDICATED SYSTEMS LTD NKA CEVA LOGI | | | SCAC4 |
| 36 | DDCT | D & D CEDAR PRODUCTS | | | SCAC4 |
| 37 | DDCU | DAL DEUTSCHE AFRIKA-LINIEN GMBH & CO | | D | BIC |
| 38 | DDCU | DEUTSCHE AFRIKA LINIEN GMBH & CO | | | SCAC4 |
| 39 | DDCV | DANDC TRUCKING LLC | | | SCAC4 |
| 40 | DDCW | DARLING-DELAWARE CO INC | | | SCAC4 |
| 41 | DDCY | D D C TRANSPORTS | | | SCAC4 |
| 42 | DDDB | D & D DISTRIBUTION | | | SCAC4 |
| 43 | DDDC | DUCAN PRODUCTS INC | | | SCAC4 |
| 44 | DDDE | DEDICATED DEPENDABLE LOGISTICS | | | SCAC4 |
| 45 | DDDI | DELAVAL DIRECT DISTRIBUTION | | | SCAC4 |
| 46 | DDDN | DEDICATED TRANSPORTATION, INC | | | SCAC1 |
| 47 | DDDT | DDD TRANSPORTATION LLC | | | SCAC4 |
| 48 | DDDU | WNG CONTAINER SERVICE CO LIMITED | | PRC | BIC |
| 49 | DDDV | DEDICATED DISTRIBUTION SERVICES INC | | | SCAC4 |
| 50 | DDDX | Frontier Cooperative Co. | added 4/1991; eliminated 10/1992; 1/1994-7/2005 (not listed) | | NAKINA |
| 51 | DDDX | Frontier Cooperative Co. | added 4/91; eliminated 10/92; 1/94-7/2000 | | NRHS |
| 52 | DDDX | FRONTIER COOPERATIVE COMPANY [RETIRED 11-30-92 ATP] | | | PWRC |
| 53 | DDDX | Frontier Cooperative | | | RSRV |
| 54 | DDDY | DAILY DIRECT DELIVERY | | | SCAC4 |
| 55 | DDEB | DISTRIBUIDORA DE EQUIPOS Y BOMBAS S | | | SCAC4 |
| 56 | DDEC | DIAMOND P TRANSPORT | | | SCAC4 |
| 57 | DDEE | DANDEE TRANSPORTATION | | | SCAC4 |
| 58 | DDEF | DOBBS DD EXPRESS | | | SCAC4 |
| 59 | DDEK | DAWN DELIVERY EXPRESS INC | | | SCAC4 |
| 60 | DDEL | DURANTE DEVELOPMENT GROUP LTD | | | SCAC4 |
| 61 | DDEM | D & D EMULSIONS INC | | | SCAC4 |
| 62 | DDER | DEDICATED EXPRESS LLC | | | SCAC4 |
| 63 | DDES | DEVONS DELIVERIES | | | SCAC4 |
| 64 | DDEU | DE DECKER - VAN RIET BVBA | | B | BIC |
| 65 | DDEU | DE DECKER-VAN RIET | | | SCAC4 |
| 66 | DDEV | D & D EXPEDITING & TRANSPORT INC | | | SCAC4 |
| 67 | DDEW | DDEW TRUCKING INC | | | SCAC4 |
| 68 | DDEX | Dupont Dow Elastomers, L.L.C. | 7/2000-7/2005; eliminated 4/2009 | | NAKINA |
| 69 | DDEX | Dupont Dow Elastomere, L.L.C. | Jul-00 | | NRHS |
| 70 | DDEX | DUPONT DOW ELASTOMERS L.L.C. | | | PWRC |
| 71 | DDEX | Dupont Dow Elastomers | | | RSRV |
| 72 | DDF | Verein 241A65 | | CH | VKM |
| 73 | DDFE | D & D FREIGHT SYSTEMS INC | | | SCAC4 |
| 74 | DDFK | DIESEL DOGS FUEL SERVICE INC | | | SCAC4 |
| 75 | DDFL | D AND D FREIGHT LINES INCORPORATED | | | SCAC4 |
| 76 | DDFM | DINSDALE FARM | | | SCAC4 |
| 77 | DDFR | DOUBLE DIAMOND TRUCKING LIMITED | | | SCAC4 |
| 78 | DDFS | DEDICATED FLEET SYSTEMS, INC | | | SCAC1 |
| 79 | DDFS | DEDICATED FLEET SYSTEMS SPECIAL COM | | | SCAC4 |
| 80 | DDFV | DISENOS DE FORMAS METALICAS S DE RL | | | SCAC4 |
| 81 | DDGD | D & D GROUP LTD | | | SCAC4 |
| 82 | DDGE | DODGE OIL COMPANY INC | | | SCAC4 |
| 83 | DDGI | DDG TRANSPORT INCORPORATED | | | SCAC4 |
| 84 | DDGL | DODSON, GLYNN INC | | | SCAC4 |
| 85 | DDGO | DODGE OIL COMPANY | | | SCAC4 |
| 86 | DDGP | DART DEDICATED (DIV OF DART | | | SCAC4 |
| 87 | DDHH | DOUBLE D HOTSHOT LLC | | | SCAC4 |
| 88 | DDHI | D D TRANSPORT & HAULERS INC | | | SCAC4 |
| 89 | DDHN | DDH TRANSPORT INC | | | SCAC4 |
| 90 | DDHT | DOODAH TRUCKING | | | SCAC4 |
| 91 | DDIA | DOUBLE DIAMOND TRANSPORT INC | | | SCAC4 |
| 92 | DDIC | DANCER DEDICATED INC | | | SCAC4 |
| 93 | DDIE | DIVA DIRECT INC | | | SCAC4 |
| 94 | DDIG | DSD TRUCKING INC | | | SCAC4 |
| 95 | DDII | DDI LOGISTICS LLC | | | SCAC4 |
| 96 | DDIK | DAKASA DISPATCH INC | | | SCAC4 |
| 97 | DDIN | DURABLE DIESEL INC | | | SCAC4 |
| 98 | DDIQ | DOOR DROP INTERMODAL INC | | | SCAC4 |
| 99 | DDIR | DIESEL DIRECT INC | | | SCAC4 |
| 100 | DDIS | DAVIS DELIVERY SERVICE, INC | | | SCAC1 |
