| Company | Search On | Records | Category | Sub category |
| D.A.Daniel & Co Ltd | DADaniel | 2 | Components | Heaters |
| DAG. Acheson Colloids Ltd | DAG | 1 | Chemicals | Colloidal Graphite |
| Dagenite. Peto And Radford | Dagenite | 99 | Components | Electrical |
| Daimler-Benz AG | DaimlerBenz | 5 | Engine Manufacturers | Non UK |
| Daimler-Motoren-Gesellschaft | DaimlerMotoren | 7 | Engine Manufacturers | Non UK |
| Dalmas Ltd | Dalmas | 1 | Consumables | Tapes |
| Damic Controls Ltd | Damic | 1 | Components | Controls |
| Dan-Air Services Ltd | DanAir | 2 | Air Transport | Airlines |
| Dancer & Hearne Bros Ltd | DancerHearne | 4 | Engineering Equipment | Jigs |
| D.Anderson & Son Ltd | DAnderson | 20 | Structures | Hangars |
| Danforth, Jackson & Co Ltd | DanforthJackson | 1 | Components | Anchor |
| Daniel Smith Ltd | DanielSmith | 2 | Testing | Test Equipment |
| Dansette Gillet | DansetteGillet | 7 | Engine Manufacturers | |
| Dargue Acetylene Gas Co Ltd | DargueAcetylene | 1 | Engineering Equipment | Welding |
| Dart Aircraft Ltd | DartAircarft | 10 | Aircraft Manufacturers | |
| Dart Spring Co | DartSpring | 7 | Components | Springs |
| Darwins Ltd | Darwins | 16 | Manufacturing | Steel |
| Dashwood Engineering Ltd | Dashwood | 1 | Manufacturing | Precision Engineering |
| Dassault. Generale Aeronautique Marcel | Dassault | 19 | Aircraft Manufacturers | Non UK |
| Davall & Sons Ltd. S. | Davall | 19 | Components | FDR |
| David Brown & Sons (Hudd) Ltd | DavidBrown | 64 | Ground Equipment | |
| David Budworth Ltd | DavidBudworth | 4 | Aircraft | Engineering |
| Davidson Aviation Co Ltd | Davidson | 6 | Aircraft Manufacturers | |
| Davidson & Co Ltd | DavidsonCo | 3 | Factory | Air Conditioning |
| Davis, Wynn & Andrews Ltd |
Davis | 1 | Testing | Vibration Equipment |
| Davis Furnace Company | DavisFurnace | 7 | Engineering Equipment | Furnaces |
| Davison. A.C. | Davison | 2 | Manufacturing | Radiators |
| Davis & Timmins Ltd | DavisTimmins | 3 | Manufacturing | AGS |
| Davu Wires & Cables | Davu | 1 | Manufacturing | Cables |
| Dawe Instruments Ltd | DaweInstruments | 14 | Instrument Manufacturers | Test Equipment |
| D.Dawnay & Sons Ltd. Archibald | Dawnay | 12 | Factory | Construction |
| D.D.D.Prescription Ltd | DDD | 6 | Health And Safety | Personal Protection |
| De Bergue's Patents Ltd | DeBergue | 11 | Manufacturing | Components |
| Decca Radar Ltd | Decca | 253 | Airfields | Air Traffic Control |
| Deissner. C. | Deissner | 9 | Engine Manufacturers | |
| Delacombe & Marechal | DelacombeMarechal | 4 | Structures | Tents |
| Delaney Gallay Ltd | DelaneyGallay | 62 | Components | Heat Exchangers |
| Delco Remy & Hyatt Ltd | DelcoRemy | 38 | Components | Electrical |
| Delta Metal Co Ltd | DeltaMetal | 1 | Manufacturing | Gears |
| Demec | Demec | 1 | Components | Electrical |
| Denbigh Engineering Co Ltd | DenbighEngineering | 1 | Engineering Equipment | Machine Tools |
| Denco Engineering Services Ltd | Denco | 1 | Factory | Air Conditioning |
| Denfords Engineering Co | Denfords | 1 | Manufacturing | Precision Engineering |
| Denis Ferranti Meters Ltd | DenisFerranti | 2 | Avionics | Headsets |
| Denny, Mott & Dickson Ltd | DennyMott | 1 | Materials | Wood |
| Dental Engineering Co | DentalEngineering | 1 | Manufacturing | Precision Engineering |
| Dent & Co & Johnson Ltd | DentJohnson | 2 | Instrument Manufacturers | Flight Instruments |
| Deperdussin Aeroplane Syndicate Ltd. British | Deperdussin | 60 | Aircraft Manufacturers | |
| Deptford Steel & Iron Works | DeptfordSteel | 2 | Finishes | Galvanising |
| Derby Aviation Ltd | DerbyAviation | 2 | Air Transport | Engineering |
| Dermatine Company Ltd | Dermatine | 3 | Manufacturing | Joints |
| Dermide Ltd | Dermide | 4 | Materials | Textiles |
| Desiderio. C.V. | Desiderio | 1 | Components | Electrical |
| Desoutter Brothers Ltd | Desoutter | 402 | Engineering Equipment | Taps And Dies |
| Detuners Ltd | Detuners | 17 | Structures | Test Equipment |
| Dex Industries Ltd | DexIndustries | 1 | Chemicals | Anti-Corrosion |
| Dexine Ltd | Dexine | 3 | Manufacturing | Rubber |
| Dexion Ltd | Dexion | 28 | Factory | Storage |
| D.G.Willett Ltd | DGWillett | 1 | Manufacturing | Repetition Work |
| De Havilland Aircraft Of Canada | DHC | 245 | Aircraft Manufacturers | Non UK |
| D.Hinton Ltd | DHinton | 1 | Engineering Equipment | Machine Tools |
| Diagrid Structures Ltd | Diagrid | 1 | Structures | Hangars |
| Dialled Despatches Ltd | DialledDespatches | 1 | Airfields | Communications |
| 'Diamond H' Switches Ltd | DiamondH | 19 | Components | Electrical |
| Diamond Screw & Cotter Co Ltd | DiamondScrew | 4 | Fasteners | Repetition Work |
| Dickson Glider | DicksonGlider | 5 | Aircraft Manufacturers | Glider |
| Directair | Directair | 1 | Air Transport | Air Charter |
| Dixon-Bate. B. | DixonBate | 1 | Airfields | Lighting |
| D Lewis Ltd | DLewis | 247 | Clothing | Flying Clothing |
| David Moseley & Sons Ltd | DMoseley | 7 | Fixtures and Fittings | Upholstery |
| Dobbie McInnes Ltd | DobbieMcInnes | 1 | ATC | Plotting Table |
| Dockers Aircraft Finishes | Dockers | 101 | Finishes | Paints |
| Doherty Motor Components Ltd | Doherty | 4 | Manufacturing | Sheet Metal Work |
| Doman Helicopters Inc | Doman | 2 | Aircraft Manufacturers | Non UK |
| Dominion Motor Spirit Co Ltd. Acme | Dominion | 3 | Fuel Suppliers | |
| Donald Macpherson & Co Ltd | DonaldMacpherson | 2 | Finishes | Paints |
| Donaldson International Airways | Donaldson | 2 | Air Transport | Airlines |
| Doncaster Airport | Doncaster | 5 | Airfields | |
| Don Everall (Aviation) Ltd | DonEverall | 1 | Aircraft | Aircraft Sales |
| Dorman & Co Ltd. W.H. | Dorman | 3 | Ground Equipment | Stationary Engines |
| Dormer. Sheffield Twist Drill & Steel Co Ltd | Dormer | 33 | Engineering Equipment | Hand Tools |
| Dornier Werke GMBH | Dornier | 44 | Aircraft Manufacturers | Non UK |
| Douglas | Douglas | 57 | Engine Manufacturers | |
| Douglas Aircraft Company | DouglasAircraft | 77 | Aircraft Manufacturers | Non UK |
| Douglas Aero Engines Ltd | DouglasEng | 2 | Engine Manufacturers | |
| Douglas Kane (Sealants) Ltd | DouglasKane | 3 | Materials | Chemicals |
| Douglas Lawson & Co Ltd | DouglasLawson | 1 | Factory | Pulleys |
| Dover Ltd | Dover | 2 | Materials | Transparencies |
| Dowding & DollLtd | DowdingDoll | 1 | Engineering Equipment | Machine Tools |
| Dowty Group | Dowty | 457 | Components | Hydraulics |
| Dreadnought Rotary Engine Co | Dradnought | 2 | Engine Manufacturers | |
| Dragonair Ltd | Dragonair | 6 | Airfields | Construction |
| Drake & Corham Ltd | DrakeCorham | 1 | Factory | Electrical Engineers |
| Drallim Industries Ltd | Drallim | 1 | Testing | Test Equipment |
| Dreadnought Rotary Engine Co | Dreadnought | 3 | Engine Manufacturers | |
| Drummond Bros Ltd | DrummondBros | 1 | Engineering Equipment | Machine Tools |
| Duckham & Co Ltd. Alexander | Duckhams | 30 | Lubricant Suppliers | |
| Dudley Drop Forging Co Ltd | DudleyDrop | 1 | Manufacturing | Forging |
| Dufaylite Developments Ltd | Dufaylite | 1 | Manufacturing | Honeycomb Structures |
| Duncan Watson & Co | DuncanWatson | 1 | Factory | Electrical |
| Dunford & Elliott (Sheffield) Ltd | DunfordElliott | 4 | Materials | Steel |
| Dunhills Ltd | Dunhills | 35 | Clothing | Flying Clothing |
| Dunkleys Ltd | Dunkleys | 1 | Manufacturing | Stampings |
| Dunlop Rubber Co Ltd | Dunlop | 590 | Wheels And Tyres | |
| Dunlop & Ranken Ltd | DunlopRanken | 4 | Manufacturing | Steel |
| Dunne. Blair Atholl Aeroplane Syndicate Ltd | Dunne | 5 | Aircraft Manufacturers | |
| Duple Bodies & Motors Ltd Aircraft Dept | Duple | 1 | Manufacturing | Sheet Metal Work |
| Duratube & Wire Ltd | Duratube | 5 | Components | Wire |
| Durex Abrasives Ltd | Durex | 6 | Finishes | Paint Spraying |
| Dutton Aircrafts | DuttonAircrafts | 1 | Training | Flying School |
| Dzus Fastener Europe Ltd | Dzus | 33 | Fasteners | Aircraft |
