TransDigm Group makes highly engineered aircraft components used in both commercial and military aircraft, including proprietary parts for which TransDigm is often the sole or primary manufacturer for a given aircraft platform. Its business model centers on acquiring companies that make proprietary, sole-source aerospace components, parts that airlines and aircraft manufacturers must continue purchasing from TransDigm since alternative suppliers or substitute parts often aren't readily available or FAA-certified. This sole-source positioning gives TransDigm significant pricing power on many of its products, since aircraft operators have limited ability to switch suppliers for components specific to a particular aircraft model. The company's revenue is tied to both new aircraft production, which drives initial component sales, and the aftermarket replacement parts business, which benefits from the large installed base of aircraft already flying that periodically need component replacement and maintenance.