TransDigm designs, manufactures, and sells highly engineered proprietary aerospace components for commercial and military aircraft. About 90% of its products are proprietary, making TransDigm the sole-source supplier for those parts. TransDigm sells through three channels: commercial aftermarket (roughly 30–35% of revenue), defense (roughly 35–40%), and commercial OEM (roughly 25–30%). Commercial aftermarket customers include airlines, MRO shops, and distributors. Defense customers include the U.S. military and allied governments, both directly and through OEMs like Lockheed Martin. Commercial OEM customers include Boeing and Airbus. Products span a wide range — actuators, ignition systems, pumps, valves, seatbelts, cockpit security systems, avionics, parachutes, and more — but share a common trait: each is a niche, critical component with high switching costs. Once a TransDigm part is designed into an aircraft, airlines and militaries must buy replacements from TransDigm for the life of that aircraft, which typically spans 25–30 years. About 55% of revenue comes from this recurring aftermarket stream, which carries significantly higher margins than OEM sales. TransDigm also prices aggressively, running price increases ahead of inflation each year given its sole-source positioning and the high cost of recertifying alternatives. TransDigm grows through organic means and acquisitions — the company has acquired 95 businesses since 1993, targeting proprietary aerospace components businesses with significant aftermarket content and applying its operating model to expand margins post-acquisition. TransDigm operates with intentionally high leverage and returns excess cash to shareholders via special dividends and buybacks.