Proponent

Proponent describes itself as the largest independent distributor of aircraft parts and supplies, and it is unusual in the sector for being entirely employee owned. It has operated under an employee stock ownership plan for more than 30 years, and it traces its history back over 50 years to Kirkhill Aircraft Parts Company. It took the Proponent name in the late 2010s, having previously traded as Kapco Global. The head office and a manufacturing site sit on the same street in Brea, California, with 14 locations worldwide and eight distribution centers across North America, Europe and Southeast Asia.

The base business is straightforward distribution across seven product families: airframe, cargo, flight deck, electrical interconnect, engine, hardware and interior. What sits on top of it is a set of supply chain services that matter more to operators than the catalogue does. Those include aircraft on ground support running around the clock, intelligent stocking driven by the company's own demand forecasting and inventory tools, custom kitting, consignment inventory, vendor consolidation for customers trying to reduce the number of suppliers they manage, and warranty and repair administration handled on behalf of both customers and manufacturers. ProCart is the e-commerce channel. On the supplier side Proponent offers global distribution, custom storefronts, parts manufacturer approval development and manufacturing capability.

The defense exposure is concentrated in specific business units rather than spread across the company, and it is worth being clear that most of the revenue is commercial aviation. HC Pacific, based in Ontario, California, is the defense arm. It is a specialized stocking distributor for land, air and sea military platforms and adds the services that distinguish defense supply from commercial distribution: kitting, military packaging specifications, just-in-time delivery and analytics feeding customer and supplier planning.

Proponent Helicopter Services in Mineral Wells, Texas is one of the largest independent suppliers of helicopter replacement parts, with a focus on Bell airframes, from major components down to hardware. Rotorcraft support of that kind crosses over readily into military and parapublic operators. Proponent Battery Services in Morfelden-Walldorf, Germany manufactures battery test equipment, distributes for Saft, Hawker, Marathon, Concorde and Gill, and holds EASA Part 145, FAA 145 and UK 145 maintenance approvals. Proponent Technical Services in Tamarac, Florida develops FAA-approved alternate parts and repairs through parts manufacturer approvals and supplemental type certificates, and operates as an FAA and EASA Part 145 repair station rated for limited instrument, limited accessory and limited emergency equipment work, including Talon LED lighting, battery repair and emergency locator transmitter programming.

The most recent addition is Avioparts of Getafe near Madrid, acquired from ProA Capital in October 2025. Founded in 1993, it supplies lubricants, chemicals, aircraft tires and maintenance logistics with a same-day dispatch model. Proponent has also been appointed exclusive global distributor for Jamco interiors aftermarket spare parts and extended a supply chain partnership with the Jordanian MRO provider Joramco.