A
- A.V. Roe
- Abadal
- ABC Motors — UK
- ABECO
- Aberg
- ABLE
- ACAE
- Accurate Automation Corp
- Adams
- Adams-Dorman
- Adams-Farwell
- Adept-Airmotive
- Adler
- Admiralty Rotary
- Adorjan & Dedics
- Advance Engines
- Advance Motor Manufacturing Company - UK
- Advanced Engine Design
- Aeolus Flugmotor
- Aerien CC
- Aermacchi
- Aero & Marine
- Aero Adventure
- Aero Bonner Ltd.
- Aero Conversions Inc.
- Aero Development (See SPEER)
- Aero Engines Ltd.
- AIDC
- Aero Motion
- Aero Motors
- Aero Pixie
- Aero Prag
- Aero Sled
- Aero Sport International
- Aero Sport Power
- Aero Thrust
- Aero Turbines Ltd
- AeroConversions
- Aerodaimler
- Aerojet — U.S.
- Aeromarine Company
- Aeromarine — U.S.
- Aeromax
- Aeromotion
- Aeronamic
- Aeronautical Engineering
- Aeronautical Manufacturing
- Aeronautical Products Corporation
- Aeronca — U.S.
- Aeronco
- Aeroplane Motors Company
- Aeroprotech
- Aerosila
- Aerosport - U.S.
- Aerostar - Romania
- Aerosud-Marvol
- Aerotech-PL
- Aerotech
- Aerotechnik
- Aerotek (USA)
- Aerotwin
- Aerovee
- AFECO
- Affordable Turbine Power
- AFR
- Agilis
- Agusta - Italy
- Ahrbecker Son and Hankers
- Aichi Kokuki - Japan
- Aiello
- Air Cooled Motors - U.S.
- Air Repair Incorporated
- Air Ryder
- Air Technical Arsenal
- Air-Craft Engine Corp
- Aircat
- Aircraft & Ind. Motor Corp.
- ACT
- AEADC
- Aircraft Engine CorporationAEC
- Aircraft Engine Develop.
- Aircraft Engine Services
- Aircraft Engine Specialists
- Aircraft Holding Corp.
- Aircraft Propeller Co.
- Airculture
- Airdelta
- Airdisco — UK
- AiResearch
- Airex
- Airmotive-Perito
- Airship
- Airways Mfg.
- AISA
- Aixro
- Ajax
- Akkerman
- Akron
- AKSAI
- Albatross
- Aldasoro
- Alexander (engine manufacturer)
- Alfa Romeo — Italy
- Alfaro
- ABEC
- Allen Aircraft Engine Co — U.S.
- Alliance=
- Allied Licensed manuf. of French Règnier 4L
- AlliedSignal - U.S.
- Allis-Chalmers
- Allison Engine Company — U.S.
- Alvis — UK
- ACE
- AEC
- American Helicopter
- American
- Angle
- Antoinette — France
- Anzani
- Ardem
- Argus Motoren — Germany
- Armstrong Siddeley — UK
- Arrow
- Arrow SNC - Italy
- Arsenal
- Ashmusen
- Aspin
- Aster
- Astra Avioane Arad - Romania
- Atwood
- Aubier & Dunne
- Austro Engine - Austria
- Austro-Daimler — Austria
- Avia Narodny Podnik (postwar)
- Avia — Czechosloviaka
- Avia (pre-war)
- Aviadvigatel
- Avio – Italy
- Avro CanadaSource: Gunston
- Avro
- Axelson
- Axial Vector Engine Corporation (Dyna-Cam)
Read more about this topic: List Of Aircraft Engine Manufacturers