Willis Lease Finance Corporation
- Acquires and provides commercial aircraft spare engines in the aftermarket and purchases and resells used and refurbished commercial aircraft engines and airframe and engine components. (Nasdaq: WLFC).
- http://www.willislease.com/

Kreisler Manufacturing Corporation
- Manufactures precision metal components and assemblies for use in military and commercial aircraft engines. (Nasdaq: KRSL).
- http://www.kreisler-ind.com/

Bayern-Chemie GmbH and Protac S.A.
- Developer and manufacturer of rocket and airbreathing propulsion systems, including hypervelocity and special use engines. Site also provides company history and profile, news, review of technologies, and related links.
- http://www.bayernchemie-protac.com/

Eggenfellner Aircraft LLC.
- Producing firewall forward engine packages based on a Subaru automotive engine conversion.
- http://www.eggenfellneraircraft.com/

Universal Turbine Parts
- Pratt and Whitney Canada approved supplier of PT6, JT15D, and PW100 engines and components.
- http://www.utpparts.com

Mallen Research Corporation
- ultra-efficient aeroengines for unmanned aerial vehicles and other performance-critical sectors.
- http://www.mallenresearch.com/

SWB Turbines Inc.
- Developer of small air-breathing engines.
- http://www.swbturbines.com

EPI, Inc.
- Design and development of piston engine technology and systems, specializing in aircraft V8 engines and propeller reduction gearboxes.
- http://www.epi-eng.com

Progressive Air Services, Aircraft Engines and Parts
- Aircraft engines, parts and accessories to worldwide market.
- http://www.progressiveair.net

Firewall Forward
- Manufacturer of Honda Civic based aircraft engines as well as propellor speed reduction units and ignition systems.
- http://www.firewall.ca/

Simonini Flying
- Two stroke engines for paramtors.
- http://www.simonini-flying.com/

MTU Aero Engines
- Manufacturer providing development, production and maintenance services for civil and military aero engines and industrial gas turbines.
- http://www.mtu.de/

Compact Radial Engines
- Manufactures and distributes radial, boxer and inline aircraft engines for experimental, PPG and ultralight aircraft.
- http://www.compactradialengines.com/

Two Stroke International
- Manufacturer of a line of lightweight engines for ultralight aircraft.
- http://www.2si.com/

Zoche Aero-Diesels
- Developing type certificated, direct drive, air cooled, radial, two-stroke Diesel engine.
- http://www.zoche.de/

Textron Lycoming
- Major manufacturer of general aviation piston engines.
- http://www.lycoming.textron.com/

DeltaHawk, Inc.
- Designing a new two-stroke diesel engine aimed at the general aviation market.
- http://www.deltahawkengines.com/

Crossflow Aero Corporation
- Converting Subaru automotive engines for experimental aircraft. [requires Flash]
- http://www.crossflow.com/

Atkins Rotary Specialties Inc.
- Supplying Mazda (RX7) rotary engines for installation in homebuilt aircraft.
- http://www.atkinsrotary.com/

Zanzottera Engines
- Manufacturer of engines designed for ultralight and unmanned aircraft.
- http://www.zanzotteraengines.com/

VW Engines
- Producing the RG2000 aircraft engine along with associated accessories.
- http://www.vw-engines.com/

Pratt and Whitney
- Leader in the design, manufacture, and support of turbine engines.
- http://www.pratt-whitney.com/

Limbach Flugmotoren
- German manufacturer of the Limbach aircraft engine. [Flash required]
- http://www.limflug.de/

Franklin Aircraft Engines, Inc.
- Manufacturer of light aircraft piston engines.
- http://www.franklinengines.com/

Vertical Technologies
- Manufacturer of turbine engines for aeronautical use. From Italy.
- http://www.verticaltechnologies.it/