| Company | Search On | Records | Category | Sub category |
| Kaman Aircraft Corporation | Kaman | 2 | Aircraft Manufacturers | Non UK |
| Kapok Ktd | Kapok | 2 | Materials | Kapok |
| Kardex Visible Control Systems | Kardex | 1 | Office Equipment | Filing Systems |
| Kautex Plastics Ltd | Kautex | 18 | Materials | Plastics |
| Kawasaki | Kawasaki | 1 | Aircraft Manufacturers | Non UK |
| Kay Brothers | KayBrothers | 1 | Chemicals | Adhesives |
| Kaylee Transfers Ltd | Kaylee | 2 | Finishes | Transfers |
| Kayser Ellison & Co Ltd | KayserEllison | 11 | Materials | Steel |
| Kelvin Bottomley & Baird Ltd | KBB | 70 | Instrument Manufacturers | Flight Instruments |
| KDG Instruments Ltd | KDG | 85 | Instrument Manufacturers | Flight Instruments |
| Kearsley & Co Ltd. Robert | Kearsley | 3 | Finishes | Paints |
| Keegan Aviation Ltd | Keegan | 33 | Aircraft Suppliers | Distributors |
| Keelavite Rotary Pumps & Motors Ltde | Keelavite | 2 | Manufacturing | Hydraulics |
| Keelbild | Keelbild | 3 | Models | Display |
| KEF Group | KEF Group | 1 | Ground Equipment | |
| Kehler & Stelling. Von | KehlerStelling | 3 | Survival Equipment | Dinghies |
| Kelson Engineering | KelsonEngineering | 1 | Manufacturing | Machining |
| Kelvin & Hughes (Aviation) Ltd | KelvinHughes | 32 | Instrument Manufacturers | Flight Instruments |
| Kelvin & James White Ltd | KelvinJames | 3 | Instrument Manufacturers | Flight Instruments |
| Kendell & Sons Ltd. T. | Kendell | 1 | Engineering Equipment | Machine Tools |
| Kenilworth Manufacturing Co Ltd | Kenilworth | 2 | Materials | Seals |
| Kenilworth Mfg Co. The | KenilworthMfg | 1 | Chemicals | Sealants |
| Kenning Aviation Ltd | KenningAviation | 1 | Ground Equipment | Transport |
| Kenrick & Jefferson Ltd | KenrickJefferson | 3 | Finance | Business Consultancy |
| Kent | Kent | 2 | Instrument Manufacturers | Fuel Systems |
| Kent Alloys Ltd | KentAlloys | 24 | Fabrication | Castings |
| Kenton Equipment Ltd | Kenton | 1 | Engineering Equipment | Weighing Machines |
| Kenton Equipment Ltd | KentonEquipment | 5 | Ground Equipment | Test Equipment |
| Kenya Airways | KenyaAirways | 1 | Air Transport | Airlines |
| Ketay Ltd | Ketay | 14 | Components | Electrical |
| Kidde Company Ltd. Walter | Kidde | 98 | Survival Equipment | Dinghies |
| Kigass Limited | Kigass | 13 | Components | Engines |
| Kilfrost Manufacturing Co Ltd | Kilfrost | 13 | Chemicals | De Icing |
| King Aircraft Corporation | KingAircraftCorp | 24 | Role Equipment | Interiors |
| King Dick Ltd. Abingdon | KingDick | 7 | Engineering Equipment | Hand Tools |
| King Radio Corporation | KingRadio | 82 | Avionics | Navigation |
| Kinnell & Co Ltd. Chas P. | Kinnell | 3 | Factory | Air Conditioning |
| Kirby Banks Screw Co Ltd | KirbyBanks | 2 | Fasteners | AGS |
| Kismet Ltd. William Turner | Kismet | 19 | Instrument Manufacturers | Test Equipment |
| Kitchen & Wade Ltd | KitchenWade | 2 | Manufacturing | Machine Tools |
| Kiveton Park Steel & Wire Works Ltd | KivetonPark | 2 | Materials | Steel |
| K.Johnson & Sons | KJohnson | 1 | Engineering Equipment | Machine Tools |
| Klemm | Klemm | 23 | Aircraft Manufacturers | Non UK |
| K.L.G..Robin Hood Engineering Works Ltd | KLG | 323 | Components | Spark Plugs |
| Klinger Ltd. Richard | Klingerit | 17 | Materials | Asbestos |
| KLM | KLM | 55 | Air Transport | Non UK |
| Knowles Oxygen Co Ltd | KnowlesOxygen | 4 | Gases | Hydrogen |
| Knox Motors Associates | KnoxMotors | 1 | Engine Manufacturers | Non UK |
| Kodak Ltd | Kodak | 30 | Role Equipment | Cameras |
| Kollsman Instrument Ltd | Kollsman | 12 | Instrument Manufacturers | Flight Instruments |
| Koolhoven. Nationale Vlietuig Industrie | Koolhoven | 3 | Aircraft Manufacturers | Non UK |
| Kovo Ltd | Kovo | 3 | Aircraft Manufacturers | Non UK |
| KRG Aircraft Company Ltd | KRG | 3 | Fabrication | Sheet Metal Work |
| Kroll & Co | Kroll | 2 | Manufacturing | Stampings |
| Kronfeld Ltd | Kronfeld | 10 | Aircraft Manufacturers | |
| Kuwait Airways | Kuwait | 1 | Air Transport | Airlines |
