H
- Hagglund, Hägglund & Söner – Sweden
- HAI, Hellenic Aerospace Industry – Greece
- Hainz, Franz Hainz – Germany
- Halberstadt, Halberstädter Flugzeug-Werke GmbH – Germany
- Hall, Cunningham-Hall Aircraft Corporation – United States
- Halsted, Barry Halsted – United States
- Hamburger Flugzeugbau, Hamburger Flugzeugbau GmbH – Germany, (1932-1940) > Blohm & Voss[1]
- Hamilton, Hamilton Aircraft Company Inc – United States
- Hamilton, Hamilton Aviation – United States
- H&E Paramotores, Madrid, Spain
- Handley Page, Handley Page (Reading) Ltd – United Kingdom
- Handley Page, Handley Page Ltd – United Kingdom, (?-1970) > Scottish Aviation
- Hannaford, Hannaford Aircraft – United States
- Hannover, Hannoversche Waggonfabrik AG – Germany
- Hanriot, Aeroplanes Hanriot et Cie – France, (1914–1936) > SNCAC
- Hansa-Brandenburg, Hansa-Brandenburg – Germany, > Heinkel
- Hanseatische Flugzeugwerke, Hanseatische Flugzeugwerke – Germany, (Hansa)
- HAPI, HAPI Engines Inc – United States
- Harbin, Harbin Aircraft Manufacturing Corporation – China, (1952–?) (HAMC)
- Harbin EMBRAER, Harbin Embraer Aircraft Industry Company Ltd – China
- Harlow, Harlow Aircraft Co. – United States
- Harmening's High Flyers, Genoa, Illinois and later in Big Stone City, South Dakota, United States
- Harmon (1), James B. Harmon – United States
- Harmon (2), D & J Harmon Co Inc – United States
- Harmon (2), Harmon Rocket LLC – United States
- Harper Aircraft Manufacturing Company, Harper Aircraft Manufacturing Company Inc. – United States
- Harris & Sheldon, Harris & Sheldon Ltd – United Kingdom
- HAT, Hellenic Aeronautical Technologies – Greece
- Hatz, John D. Hatz – United States
- HAVELSAN, Hava Elektronik Sanayi (Air Electronic Industries) – Turkey
- Hawker, Hawker Aircraft Ltd – United Kingdom, (1920–1961) > Hawker Siddeley
- Hawker De Havilland, Hawker De Havilland Australia Pty Ltd – Australia
- Hawker De Havilland, Hawker De Havilland Ltd – Australia
- Hawker Pacific Aerospace, Hawker Pacific Aerospace – United Kingdom, (1980–present)
- Hawker Siddeley, Hawker Siddeley Aviation Ltd – United Kingdom
- Hawksley, A W Hawksley Ltd. – United Kingdom
- HB-Aircraft, HB-Aircraft Industries Luftfahrzeug AG – Austria
- HB-Flugtechnik, HB-Flugtechnik GmbH – Austria
- HBN, HBN Group – United Kingdom/France, (Hawker, Breguet and Nord-Aviation)
- Heinkel, Ernst Heinkel AG – Germany, (?-1959) > FUS
- Heintz, Christophe Heintz – France
- Helibras, Helicópteros do Brasil SA – Brazil
- Helikopter Services, Helikopter Services – Unknown
- Helio, Helio Aircraft Company – United States
- Helio, Helio Aircraft Corporation – United States
- Helio, Helio Aircraft Ltd – United States
- Heliopolis, Heliopolis Air Works – Egypt
- Helipro, Helipro Corporation International – United States
- Heli-Sport, CH-7 Heli-Sport Srl., Torino, Italy
- Helwan, Helwan Air Works – Egypt
- Henderson, Henderson Aero Specialties Inc – United States
- Henschel, Henschel & Son – Germany
- Hermeus, Hermeus Corporation – United States
- HESA, IRan Aircraft Industries – Iran
- Heston Aircraft, Heston Aircraft Co. Ltd. – United Kingdom
- HFB, Hamburger Flugzeugbau GmbH – Germany, (postwar) > Messerschmitt-Bölkow-Blohm (MBB)
- Highlander, Highlander Aircraft Corporation – United States
- Hillberg Helicopters, Fountain Valley, California, United States
- Hiller, Hiller Aircraft Company Inc – United States
- Hiller, Hiller Aircraft Corporation – United States
- Hiller, Hiller Aviation Inc – United States
- Hiller, Hiller Helicopters – United States
- Hiller, Hiller Helicopters Inc – United States
- Hindustan Aeronautics Limited, Bangalore, India
- Hindustan, Hindustan Aircraft Ltd – India
- Hiro Naval Arsenal, Hiro Naval Arsenal – Japan
- Hirth, Wolf Hirth GmbH – Germany
- Hispano, La Hispano Aviación S.A. – Spain, (?-1972) > CASA
- Hispano-Suiza, Hispano-Suiza – Spain, France
- Historical Aircraft, Historical Aircraft Corporation – United States
- HK, HK Aircraft Technology AG – Germany
- HOAC, HOAC Austria Flugzeugwerk Wiener Neustadt GmbH – Austria
- Hoffmann, Hoffmann Aircraft Flugzeugproduktion und Entwicklung GmbH – Austria
- Hoffmann, Hoffmann Flugzeugbau-Friesach GmbH – Austria
- Hoffmann, Wolf Hoffmann Flugzeugbau KG – Germany
- Holcomb, Jerry Holcomb – United States
- Hollmann, Martin Hollmann – United States
- Honda Aircraft Company, subsidiary of Honda Motor Company Ltd – Japan
- Honda-Mississippi, Honda & Mississippi State University – Japan/United States
- Hongdu, Hongdu Aviation Industry Group – China
- Hovey, Robert W. Hovey – United States
- Howard (1), Howard Aircraft Corporation – United States
- Howard (2), Howard Aero Inc – United States
- Howard (2), Howard Aero Manufacturing Division of Business Aircraft Corporation – United States
- Howard Hughes Engineering, Howard Hughes Engineering Pty Ltd – Australia
- HPA, High Performance Aircraft GmbH & Co KG – Germany
- Huff-Daland, Huff-Daland – United States, (1920–1933) (Ogdensburg Aeroway Corp.) > Huff-Daland Aero Corporation > Huff-Daland Aero Company > Keystone Aircraft Corporation
- Hughes, Hughes Helicopters Division of Summa Corporation – United States
- Hughes, Hughes Helicopters Inc – United States
- Hughes, Hughes Tool Company, Aircraft Division – United States
- Humbert Aviation, Ramonchamp, France
- Hummel Aviation, J. Morry Hummel, Bryan, Ohio, United States
- Hunting, Hunting Aircraft Ltd – United Kingdom, (1957–1959) > British Aircraft Corporation
- Hunting Percival, Hunting Percival Aircraft Ltd – United Kingdom
- Hurel-Dubois, Société de Construction des Avions Hurel-Dubois – France
- Hybrid Aircraft Corporation – United States
- Hydroplane, Gidroplan ooo – Russia
- Hydroplane, Hydroplane Ltd – Russia
- Hynes, Hynes Helicopter Inc – United States
- Hyundai, Hyundai Precision Industry – South Korea, > Korea Aerospace Industries