| Company | Search On | Records | Category | Sub category |
| 3M Company | 3M | 12 | Materials | Chemicals |
| The Automobile Association | AA | 6 | Motoring | Organisations |
| The Aabacas Engineering Co Ltd | AabacasEngineering | 1 | Factory | Cranes |
| Automobile & Aircraft Services Ltd | AandA | 1 | Air Transport | Air Charter |
| Abbey Panel & Sheet Metal Co Ltd | AbbeyPanel | 28 | Maintenance | Sheet Metal Work |
| A B C Motors Ltd | ABC | 47 | Engine Manufacturers | |
| Abrasive Developments Ltd | AbrasiveDevelopments | 6 | Engineering Equipment | Abrasives |
| Access Equipment Ltd | AccessEquipment | 1 | Ground Equipment | Aircraft Handling |
| Accles and Pollock Ltd | AcclesandPollock | 133 | Fabrication | Tubing |
| The A-C Construction Co | ACConstruction | 1 | Structures | Roofing |
| Accurate Recording Instrument Co | Accurate | 20 | Instrument Manufacturers | |
| AC Electronics | ACElectronics | 16 | Avionics | Navigation |
| The Acetylene Corporation Ltd | AcetyleneCorp | 4 | Gases | Acetylene |
| Acetylene Equipment Co Ltd | AcetyleneEquipment | 1 | Engineering Equipment | Welding |
| Acetylene Illuminating Co Ltd | AcetyleneIlluminating | 2 | Fabrication | Welding |
| Acorn Anodising Co Ltd | AcornAnodising | 3 | Finishes | Anodising |
| Acorn Spring Works | AcornSprings | 1 | Components | Springs |
| A.C.Sphinx Sparking Plug Co Ltd | ACSphinx | 14 | Components | Spark Plugs |
| Acton Bolt Ltd | ActonBolt | 7 | Manufacturing | AGS |
| A.C. Wickman Ltd | ACWickman | 16 | Engineering Equipment | Multi Spindle Automatics |
| Adamant Engineering Co Ltd | Adamant | 2 | Manufacturing | Sheet Metal Work |
| The Adamite Company Ltd | Adamite | 1 | Structures | Concrete |
| Aircraft Disposal Co Ltd | ADC | 154 | Aircraft Suppliers | |
| A D C Engine Ltd | ADCEngines | 1 | Maintenance | Aircraft |
| Adcola Products Ltd | Adcola | 16 | Engineering Equipment | Hand Tools |
| A.D.Keeling Ltd | ADKeeling | 2 | Materials | Scrap Metal |
| Rhon Adler & Bussard | AdlerBussard | 1 | Aircraft Manufacturers | Glider |
| Advance Motor Mfg Co Ltd | AdvanceMotor | 1 | Engine Manufacturers | |
| Adwest Engineering Ltd | AdwestEngineering | 1 | Components | Electrical |
| A.E.Griffiths (Smethwick) Ltd | AEGriffiths | 2 | Factory | Air Conditioning |
| AEG-Telefunken | AEGTelefunken | 2 | Airfields | Radar |
| Associated Electrical Industries Ltd | AEI | 63 | Components | Electrical |
| A E Jones Ltd | Aejones | 17 | Models | Flying |
| A.E.Newton Ltd | AENewton | 1 | Lubricant Suppliers | |
| Aviation & Engineering Projects Ltd | AEP | 1 | Collaboration | Consultancy |
| Aeraspray Mfg Co Ltd | Aeraspray | 10 | Finishes | Paint Spraying |
| Aerators Ltd | Aerators | 4 | Manufacturing | Castings |
| Aerial Manufacturing Company Of Great Britain & Ireland Ltd | AerialManufacturingCo | 23 | Aircraft Manufacturers | |
| Aerial Products Inc | AerialProducts | 2 | Survival Equipment | Pyrotechnics |
| Aerial Sites Ltd | AerialSites | 1 | Aerial Work | Aerial Advertising |
| Aerial Survey Co (Newfoundland) Ltd | AerialSurvey | 2 | Aerial Work | Air Survey |
| Aeritalia | Aeritalia | 15 | Aircraft Manufacturers | Non UK |
| Aer Lingus | AerLingus | 9 | Air Transport | Airlines |
| Aer Macchi | AerMacchi | 42 | Aircraft Manufacturers | Non UK |
| Aero Aircraft Works (Prague) | Aero | 1 | Aircraft Manufacturers | Non UK |
| College Of Aeronautical Engineering | AeroCollege | 3 | Training | Engineering |
| Atlantic Commander Ltd Gatwick | AeroCommander | 1 | Aircraft Manufacturers | Non UK |
| Aerocontacts Ltd | Aerocontacts | 33 | Airfields | Air Traffic Control |
| Aero Controls Ltd | AeroControls | 18 | Fasteners | AGS |
| Aero Coverings Ltd | AeroCoverings | 3 | Finishes | Paints |
| Aero-Docks | AeroDocks | 3 | Ground Equipment | Docks |
| Aero Engines Ltd | AeroEngines | 7 | Engine Manufacturers | |
| Aerofilms Ltd | Aerofilms | 5 | Aerial Work | Photography |
| Aerograph Co Ltd | Aerograph | 122 | Finishes | Paints |
| Aerolex Ltd | Aerolex | 17 | Manufacturing | Components |
| Aerolite Piston Co Ltd | Aerolite | 4 | Components | Pistons |
| Aero Maintenance Equipment Ltd | AeroMaintenance | 1 | Ground Equipment | Jacks |
| The Aero Mechanical Co Ltd | AeroMechanical | 1 | Manufacturing | Components |
| Aeromodels Ltd | Aeromodels | 16 | Models | Display |
| Aero & Motor Company | AeroMotor | 1 | Aeronautical Engineers | |
| Aeronautical and Panel Plywood Co Ltd | Aeronautical and Panel | 35 | Materials | Wood |
| Aeronautical Accessories | AeronauticalAccessories | 11 | Clothing | Flying Clothing |
| Aeronautical Radio Services Ltd | AeronauticalRadioServices | 5 | Maintenance | Radio |
| Aeronautical Syndicate | AeronauticalSyndicate | 21 | Aircraft Manufacturers | |
| Aeronauts Ltd | Aeronauts | 1 | Manufacturing | Components |
| Aeronca. Light Aircraft Ltd | Aeronca | 12 | Aircraft Manufacturers | |
| Aeroparts Engineering Co Ltd | Aeroparts | 5 | Manufacturing | Assemblies |
| Aeroplane & Motor Aluminium Castings Ltd | AeroplaneCastings | 2 | Manufacturing | Castings |
| Aeroplane Supply Company | AeroplaneSupply | 24 | Aircraft Suppliers | |
| Aeroplastics Ltd | Aeroplastics | 2 | Manufacturing | Plastics |
| Aero Research Ltd | AeroResearch | 44 | Materials | Bonding |
| Aeros Ltd | Aeros | 17 | Aerial Work | Agency |
| Aeroservices (London) Ltd | Aeroservices | 4 | Aircraft Suppliers | |
| Aero-Spares Co | AeroSpares | 2 | Distributors | |
| Aerospatiale | Aerospatiale | 175 | Aircraft Manufacturers | Non UK |
| Aerostyle Ltd | Aerostyle | 2 | Finishes | Paint Spraying |
| Aerotec Industries | Aerotec | 14 | Components | Seating |
| Aerotherm. UOP | Aerotherm | 20 | Components | Seating |
| Aerovías Quisqueyana | AeroviasQuisqueyana | 1 | Air Transport | Airlines |
| Aircraft Ground Equipment | AGE | 5 | Ground Equipment | Test Equipment |
| Office d'Aviation | Agencies | 1 | Aircraft Suppliers | Non UK |
| Agfa Photo Ltd | Agfa | 1 | Role Equipment | Photography |
| Kirby Banks Screw Co Ltd | AGS | 5 | Aircraft Parts | Accessories |
| Aeroplane General Sundries Ltd | AGSLtd | 26 | Consumables | AGS |
| A.G.S Mfg Co Ltd | AGSMfg | 4 | Fasteners | AGS |
| A.G.Sutherland Ltd | AGSutherland | 2 | Manufacturing | Sheet Metal Work |
| Construzioni Aeronautiche Giovanni Agusta | Agusta | 29 | Aircraft Manufacturers | Non UK |
| Air Industrial Developments Ltd | AID | 8 | Engineering Equipment | Paint Spraying |
| Aipite Products Ltd | Aipite | 1 | Components | Gaskets |
| Air Navigation Co Ltd |
Air Navigation |
1 | | |
| Air New Zealand | AirNewZealand | 2 | Air Transport | Airlines |
| Air Anglia | AirAnglia | 2 | Air Transport | Airlines |
| Airbus Industrie | Airbus | 65 | Aircraft Manufacturers | Collaboration |
| Air Charter Ltd | AirCharter | 18 | Air Transport | Airlines |
| Airco | Airco | 12 | Aircraft Parts | Distributors |
| Air Coupe | AirCoupe | 2 | Aircraft Manufacturers | |
| Air Couriers Ltd | AirCouriers | 5 | Aerial Work | Aircraft Sales |
| Aircraft Accessories Ltd | AircraftAccessories | 5 | Aircraft Parts | Accessories |
| Aircraft Company | AircraftCo | 13 | Aircraft Suppliers | |
| Aircraft Components Ltd | AircraftComponents | 5 | Components | Undercarriages |
| Aircraft Computers & Calculators | AircraftComputers | 2 | Pilot Supplies | Navigation |
| Aircraft Construction Co | AircraftConstructionCo | 7 | Manufacturing | Components |
| Aircraft Distributors Ltd | AircraftDistributors | 30 | Sales & Brokerage | Aircraft |
| Aircraft Engineering & Jigs Ltd | AircraftEngJigs | 7 | Manufacturing | Jigs |
| Aircraft Equipment (Camberley) Ltd | AircraftEquipment | 1 | Weapons | |
| Aircraft Furnishing Ltd | AircraftFurnishing | 22 | Components | Cabin Seating |
| Aircraft General Supplies & Petronic Ltd | AircraftGenSupplies | 1 | Aircraft Parts | AGS |
| Aircraft Improvements Co | AircraftImprovements | 5 | Aircraft Suppliers | Seaplanes |
| Aircraft Industries Of Canada | AircraftIndustCanada | 1 | Aircraft Manufacturers | Non UK |
| Aircraftings Ltd | Aircraftings | 8 | Components | Fuel Systems |
| Aircraft Manufacturing Co Ltd | AircraftManufacturingCo | 15 | Aircraft Manufacturers | |
| Aircraft-Marine Products (GT Britain) Ltd | AircraftMarine | 6 | Components | Electrical |
| Aircraft Materials Ltd | AircraftMaterials | 36 | Components | AGS |
| Aircraft Operating Co Ltd | AircraftOperatingCo | 2 | Aerial Work | Air Charter |
| Aircraft Precision Ltd | AircraftPrecision | 2 | Manufacturing | Components |
| Aircraft Steel Structures Ltd | AircraftSteelStructures | 3 | Manufacturing | Precision Engineering |
| Aircraft Supplies Company | AircraftSuppliesCo | 134 | Aircraft Suppliers | |
| Aircraft Transport & Travel Ltd | AircraftTransport | 12 | Air Transport | Airlines |
| An Open Letter | Aircrew | 1 | Recruitment | Pilots |
| Air-Dispatch Ltd | AirDispatch | 2 | Air Transport | Airlines |
| Airedale Light Alloys | AiredaleAlloys | 1 | Manufacturing | Castings |
| Air Engine Services (U.S.-U.K.) Ltd | AirEngineServices | 5 | Maintenance | Engines |
| Alan Cobham Aviation Ltd | Airfields | 38 | Airfields | Consultancy |
| Airfields Autohire Ltd | AirfieldsAutohire | 1 | Airport Services | Car Hire |
| Airfix | Airfix | 56 | Models | Display |
| Airflow Streamlines Ltd | AirflowStreamlines | 2 | Manufacturing | Seaplanes |
| Air France | AirFrance | 61 | Air Transport | Airlines |
| Air Hire Ltd | AirHire | 6 | Air Transport | Aircraft Hire |
| Air-India International | AirIndia | 43 | Air Transport | Airlines |
| Airline Air Spares Ltd | AirlineAirSpares | 9 | Aircraft Parts | Spares |
| C.M.A . Air Lines | Airlines | 3 | Air Transport | Airlines |
| Air Log Co Ltd | AirLog | 14 | Instrument Manufacturers | Flight Instruments |
| Air Malawi | AirMalawi | 1 | Air Transport | Airlines |
| Airmed Ltd | Airmed | 56 | Avionics | Radio |
| Air New Zealand | AirNewZealand | 2 | Air Transport | Airlines |
| Air Parts Ltd | AirParts | 1 | Aircraft Parts | AGS |
| The Airscrew Company Ltd | Airscrew | 265 | Components | Propellers |
| The Airship Development Company | AirshipDevelopment | 1 | Aircraft Manufacturers | Airships |
| Airships Ltd | AirshipsLtd | 8 | Aircraft Manufacturers | Airships |
| Airspares | Airspares | 1 | Collaboration | Consultancy |
| Airspeed Ltd | Airspeed | 350 | Aircraft Manufacturers | |
| Air Survey Co Ltd | AirSurvey | 11 | Aerial Work | Air Survey |
| Air Tech Ltd | Airtech | 27 | Components | Fire Safety |
| Air Touring Shops Ltd | Airtour | 3 | Pilot Supplies | |
| Air Trainers Ltd | AirTrainers | 57 | Training | Flight Simulation |
| Air Transport (Charter) (C.I.) Ltd | AirTransport | 2 | Maintenance | Contractors |
| Air Transport (Charter) (C.I.) Ltd | AirTransportCharter | 2 | Testing | Test Equipment |
| Air Travel Ltd | AirTravel | 7 | Air Transport | Aircraft Hire |
| Air Union | AirUnion | 4 | Air Transport | Airlines |
| Air Ventures Ltd | AirVentures | 1 | Components | Fuel Tanks |
| Airwork Ltd | Airwork | 245 | Training | Flying |
| Aiton & Co Ltd | Aiton | 1 | Testing | Test Equipment |
| A.J.Ashdown Ltd | AJAshdown | 1 | Engineering Equipment | Rotoscope |
| A. & J.Main & Co | AJMain | 2 | Structures | Hangars |
| A.Joseph | AJoseph | 1 | Materials | Scrap Metal |
| A.J.Pratt & Sons Ltd | AJPratt | 1 | Ground Equipment | Chains |
| A.J.Walter Ltd | AJWalter | 8 | Aircraft Suppliers | Aircraft Sales |
| A.J.W. (Instruments) Ltd | AJWInstruments | 3 | Aircraft Parts | Suppliers |
| A.K.Fans Ltd | AKFans | 1 | Components | Fans |
| Aland & Co | Aland | 2 | Engineering Equipment | Blowers |
| Alardux Co | Alardux | 1 | Consumables | Welding |
| A & A J Law | ALaw | 5 | Airfields | Hangars |
| Albion Drop Forgings Ltd | AlbionDrop | 3 | Manufacturing | Forging |
| Alcan Industries Ltd | Alcan | 8 | Materials | Aluminium |
| Alcoa International | AlcoaInternational | 1 | Manufacturing | Aluminium |
| Aldermaston Airport | Aldermaston | 1 | Training | Flying School |
| Aldis Brothers | Aldis | 1 | Airfields | Accessories |
| Alex Mosses Ltd | AlexMosses | 2 | Components | Radiators |
| Alfa-Laval Co.Ltd | AlfaLaval | 1 | Engineering Equipment | |
| Alfa Romeo Aviazione | AlfaRomeo | 1 | Engine Manufacturers | Non UK |
| Alfred Adams & Co Ltd | AlfredAdams | 2 | Chemicals | Adhesives |
| Alfred Herbert Ltd | AlfredHerbert | 15 | Health And Safety | First Aid Kits |
| Alfred P.Mill | AlfredMill | 7 | Components | Bearings |
| Alfred Partridge & Co Ltd | AlfredPartridge | 2 | Manufacturing | Components |
| Alidair Ltd | Alidair | 1 | Aircraft Suppliers | Aircraft Sales |
| Alitalia | Alitalia | 7 | Air Transport | Airlines |
| Alkit Ltd | Alkit | 8 | Clothing | Flying Clothing |
| Allcock Manufacturing Co | AllcockManufacturing | 1 | Manufacturing | Cables |
| Alldays & Onions Ltd | AlldaysOnions | 3 | Engineering Equipment | Welding |
| Allegheny | Allegheny | 1 | Air Transport | Airlines |
| Allen-Liversidge Ltd | AllenLiversidge | 1 | Engineering Equipment | Welding |
| Allen Aircraft Radio Inc | AllenRadio | 3 | Avionics | Avionics |
| Allen & Simmonds Ltd | AllenSimmonds | 8 | Components | Piston Rings |
| Allgood Manufacturing Co Ltd | Allgood | 1 | Components | Cables |
| Alliance Aeroplane Co Ltd | AllianceAero | 5 | Weapons | |
| Allied Aircraft Varnish Co Ltd | AlliedVarnish | 3 | Materials | Dope |
| Allin & Newbold Ltd | AllinNewbold | 2 | Manufacturing | Sheet Metal Work |
| Allison | Allison | 24 | Engine Manufacturers | Non UK |
| Alltools Ltd | Alltools | 2 | Manufacturing | Precision Engineering |
| Almagam Ltd | Almagam | 3 | Materials | Rubber |
| Alamarco Ltd | Almarco | 1 | Manufacturing | Machine Tools |
| Almex Ltd | Almex | 1 | Materials | Tungum |
| Almin Ltd | Almin | 2 | Materials | Aluminium |
| Alumilite &Alzak Ltd | AlumiliteAlzac | 2 | Finishes | Metals |
| Aluminium Union Ltd | AluminionUnion | 21 | Materials | Aluminium |
| Aluminium Castings Co Ltd | AluminiumCastings | 1 | Manufacturing | Castings |
| Aluminium Corporation Ltd | AluminiumCorporation | 19 | Materials | Aluminium |
| Aluminium (II) Ltd | AluminiumLtd | 8 | Materials | Aluminium Alloys |
| Aluminium Plant & Vessel Company Ltd.The | AluminiumPlant | 9 | Manufacturing | Aluminium |
| Alvaston Motors | Alvaston | 10 | Engine Manufacturers | |
| Alvis Ltd | Alvis | 279 | Engine Manufacturers | |
| Always Welding Ltd | AlwaysWelding | 3 | Vehicles | Fire & Rescue |
| Alwin Engineering Co Ltd | AlwinEngineering | 2 | Manufacturing | Components |
| A.Macnair & Co Ltd | AMacnair | 1 | Finishes | Shellac |
| Amal Ltd | Amal | 32 | Components | AGS |
| Amalgamated Carburetters Ltd | AmalgamatedCarburetters | 1 | Testing | Test Equipment |
| Amber Oils Ltd | AmberOils | 3 | Chemicals | Anti Corrosion |
| Ambrosini. Soceieta Aeronautica Italiana | Ambrosini | 3 | Aircraft Manufacturers | |
| A.Melcombe | AMelcombe | 3 | Aircraft Parts | Stockists |
| American Airlines | AmericanAirlines | 1 | Air Transport | Airlines |
| American Avitron | AmericanAvitron | 2 | Avionics | Electronics |
| American Lead Pencil Co | AmericanLeadPencil | 2 | Engineering Equipment | Drafting |
| Ames Industrial | AmesIndustrial | 8 | Engine Manufacturers | |
| A & M.Fell Ltd | AMFell | 1 | Manufacturing | Precision Engineering |
| Amherst Villiers Superchargers Ltd | AmherstVilliers | 1 | Components | Superchargers |
| Ampep Industrial Products Ltd | Ampep | 1 | Components | Bearings |
| Amphenol (Great Britain) Ltd | Amphenol | 23 | Components | Electrical |
| Amplivox Ltd | Amplivox | 13 | Avionics | Radio |
| Ancillary Developments Ltd | AncillaryDevelopments | 2 | Components | Autopilots |
| A.N.Clark (Engineers) Ltd | ANClark | 1 | Testing | Test Equipment |
| Andre Components Ltd | AndreComponents | 1 | Manufacturing | Machining |
| Andrew Fraser & Co Ltd | AndrewFraser | 4 | Engineering Equipment | Hydraulics |
| The Anger Manufacturing & Supply Co Ltd | AngerMfg | 2 | Aeronautical Engineers | |
| Anglo-American Oil Co., Ltd | AngloAmerican | 33 | Lubricant Suppliers | |
| Anglo-American Vulcanized Fibre Co Ltd. | AngloAmericanVulc | 1 | Components | Electrical |
| Anglo Scottish Trading Co | AngloScottish | 1 | Engineering Equipment | Machine Tools |
| Anodising & Platings Ltd | AnodisingPlatings | 5 | Finishes | Platings |
| Anticoustic Company | Anticoustic | 10 | Avionics | Radio |
| Antifyre Ltd | Antifyre | 2 | Survival Equipment | Fire Safety |
| Anzani | Anzani | 55 | Engine Manufacturers | |
| Appleby & Ireland Ltd | Apland | 1 | Instrument Manufacturers | Air Traffic Control |
| Automotive Products Co Ltd | APLockheed | 303 | Components | Hydraulics |
| Apollo Mfg Co | ApolloMFG | 3 | Components | Spark Plugs |
| Appleby & Ireland Ltd | ApplebyIreland | 3 | Instrument Manufacturers | |
| Aquascutum Ltd | Aquascutum | 1 | Clothing | Flying Clothing |
| Arado | Arado | 10 | Aircraft Manufacturers | Non UK |
| Arbenz.A. | Arbenz | 3 | Fasteners | Fasteners |
| Aircraft Radio Corporation | ARC | 7 | Avionics | Radio |
| Archdale. James & Co Ltd | Archdale | 34 | Engineering Equipment | |
| Ardente Acoustic Laboratories Ltd | ArdenteAcoustic | 2 | Airfields | PA Broadcast Systems |
| Ardrox Ltd | Ardrox | 3 | Testing | NDT |
| Arens Controls Ltd | Arens | 16 | Components | Controls |
| Aerolineas Argentinas | Argentinas | 2 | Air Transport | Airlines |
| Argus Motoren Gesellschaft mbH | Argus | 1 | Engine Manufacturers | Non UK |
| Accurate Recording Instrument Co | ARIC | 4 | Instrument Manufacturers | Flight Instruments |
| Armature Manufacturing Co.The | ArmatureManufacturing | 2 | Testing | Test Equipment |
| Armco Ltd | Armco | 1 | Manufacturing | Tubing |
| Armoride Ltd | Armoride | 7 | Materials | Leather |
| Armstrong Siddeley Motors Ltd |
Armstrong Siddeley |
512 | Aero Engines / Vehicles | |
| Armstrong Whitworth and Co Ltd.. Sir W. G. | Armstrong Whitworth | 300 | Aircraft Manufacturers | |
| Armstrong Patents | ArmstrongPatents | 12 | Fasteners | Thread Inserts |
| Arnott & Harrison Ltd | ArnottHarrison | 8 | Aircraft | Engineering |
| Arrol. Sir William & Co Ltd | Arrol | 1 | Engineering Equipment | Test Equipment |
| Arrol Johnston Ltd | ArrolJohnston | 21 | Vehicles | Cars |
| Arrow Aircraft (Leeds) Ltd | Arrow | 3 | Aircraft Manufacturers | |
| Arthur Lee & Sons | Arthur Lee | 1 | Materials | Steel |
| Arthur Balfour & Co Ltd | ArthurBalfour | 4 | Engineering Equipment | Machine Tools |
| Arthur Lee & Sons | ArthurLee | 41 | Manufacturing | Wire |
| Arthur Robinson & Sons (Willenhall) Ltd | ArthurRobinson | 1 | Manufacturing | Forging |
| A.S.Boyle & Co Ltd | ASBoyle | 1 | Lubricant Suppliers | Oil |
| Ashdowns Ltd | Ashdowns | 2 | Materials | Fibre Glass |
| Askania-Werke | Askania | 30 | Instrument Manufacturers | Flight Instruments |
| Aeronautical Syndicate Ltd | ASL | 3 | Training | Flying School |
| Air Service Training Ltd | AST | 198 | Training | Flying |
| Aston Construction Co Ltd. The | AstonConstruction | 1 | Structures | Hangars |
| Astralux Ltd | Astralux | 2 | Manufacturing | Precision Engineering |
| A.Sweeten Ltd | ASweeten | 8 | Models | Flying |
| Atalanta Engineers | Atalanta | 2 | Manufacturing | Precision Engineering |
| ATC Analog Training Computers Inc | ATCAnalog | 2 | Training | Flight Simulation |
| Air Transport College Ltd | ATCL | 4 | Training | Classroom |
| Atlas Air Services Ltd | AtlasAir | 4 | Training | Flying School |
| The Atlas Diesel Company Ltd | AtlasDiesel | 3 | Ground Equipment | Compressors |
| Atlas Lighting Ltd | AtlasLighting | 4 | Airfields | Lighting |
| Atlas Metal & Alloys Co Ltd | AtlasMetal | 1 | Materials | Aluminium Alloys |
| Attewell | Attewell | 11 | Components | AGS |
| Auster Aircraft | Auster | 54 | Aircraft Manufacturers | |
| Auster Birmingham | Auster Birmingham | 35 | Fixtures and Fittings | Fairings |
| The Austin Motor Co Ltd | Austin | 4 | Aircraft Manufacturers | |
| Austin Reed's | Austin Reeds | 0 | | |
| Austrian-Daimler Motor Co Ltd | AustroDaimler | 2 | Engine Manufacturers | |
| Autair Ltd | Autair | 12 | Aircraft Suppliers | Distributors |
| Auto Auctions Ltd | AutoAuctions | 1 | Sales & Brokerage | Aircraft |
| Auto-Controller Co | AutoController | 3 | Consumables | Solder |
| Auto Diesels Ltd | AutoDiesels | 32 | Ground Equipment | Ground Power Units |
| Autogiro (Cierva Autogiro Co Ltd) | Autogiro | 127 | Aircraft Manufacturers | Rotary Wing |
| Auto-Klean Strainers Ltd | AutoKlean | 16 | Components | Filters |
| Automatic Telegraph Co | AutomaticTelegraph | 2 | Avionics | Wireless |
| The Automatic Telephone & Electric Co | AutomaticTelephone | 2 | Components | Cables |
| Autometric Pumps Ltd | AutometricPumps | 1 | Engineering Equipment | Pumps |
| Automobile (Misc) | Automobile & Aircraft Services | 0 |
Vehicles | |
| Automobile & Aerial Supply Co | AutomobileAerial | 4 | Models | Flying |
| Automotive Engineering Co Ltd | AutomotiveEngineering | 1 | Manufacturing | Circlips |
| Automotive Spares Ltd | AutomotiveSpares | 1 | Materials | Sealants |
| Autonetics (North American Aviation) | Autonetics | 9 | Avionics | Radar |
| Auto-Radiators Ltd | AutoRadiators | 3 | Manufacturing | Sheet Metal Work |
| Autoset (Production) Ltd | Autoset | 11 | Factory | Storage |
| Avanti Manufacturing Co | AvantiPropeller | 1 | Components | Propellers |
| Avco Lycoming | AvcoLycoming | 25 | Engine Manufacturers | Non UK |
| Aviation Communications Ltd | Avcom | 2 | Sales & Brokerage | Avionics |
| Aviation Developments Ltd | Avdel | 34 | Fasteners | Riveting |
| Avery W.&T.Ltd | Avery | 13 | Engineering Equipment | Weighing |
| Avery-Hardoll Ltd | AveryHardoll | 30 | Components | Refuelling |
| Avery's | Averys | 2 | Aircraft Constructors | |
| Avia (Prague) | Avia | 3 | Aircraft Manufacturers | Non UK |
| Aviaexport | AviaExport | 13 | Aircraft Manufacturers | Non UK |
| Aviation Corporates Ltd | AviationCorporates | 9 | Components | Hydraulics |
| Aviation & General Insurance Co | AviationGeneral | 19 | Finance | Insurance |
| Aviation Servicing Ltd | AviationServicing | 3 | Maintenance | Aircraft |
| Aviation Traders Ltd | AviationTraders | 140 | Maintenance | Contractors |
| Avica Equipment Ltd | Avica | 106 | Components | Piping |
| Avimo Ltd | Avimo | 38 | Manufacturing | Components |
| Avion Float Co | AvionFloats | 1 | Components | Floats |
| Avionics Ltd | AvionicsLtd | 3 | Aircraft Parts | Radio |
| Avionine | Avionine | 1 | Finishes | Non UK |
| Aviquipo Inc | Aviquipo | 3 | Ground Equipment | Ground Power Units |
| Scottish Aeroplane Syndicate | Avis | 5 | Aircraft Manufacturers | |
| Automatic Coil Winder & Electrical Equipment Co Ltd
(AVO) | AVO | 39 | Maintenance | Electrical |
| Avon India Rubber Co Ltd | Avon | 1 | Wheels And Tyres | |
| A.V.Roe & Co Ltd | Avro | 815 | Aircraft Manufacturers | |
| A.Wells & Co Ltd | AWells | 1 | Components | Mountings |
| A .West & Partners | AWest | 14 | Engineering Equipment | Drafting |
| A.W.Smith & Co | AWSmith | 2 | Manufacturing | Forging |
| Aylings | Aylings | 1 | Manufacturing | Components |
| Ayres Corporation | Ayres | 1 | Aircraft Manufacturers | Non UK |
