Willis Lease Finance Corporation operates as a lessor and servicer of commercial aircraft and aircraft engines worldwide. The company operates through two segments, Leasing and Related Operations, and Spare Parts Sales. The Leasing and Related Operations segment engages in acquiring and leasing commercial aircraft, aircraft engines, and other aircraft equipment, as well as the purchase and resale of commercial aircraft engines and other aircraft equipment, and other related businesses. The Spare Parts Sales segment purchases and resells after-market engine parts, whole engines, engine modules, and portable aircraft components. The company also focuses on engine management and consulting business. It serves commercial aircraft operators, as well as maintenance, repair, and overhaul organizations. As of December 31, 2023, it had a total lease portfolio of 337 engines, 12 aircraft, one marine vessel, and other leased parts and equipment, and with 74 lessees in 42 countries; and managed a total lease portfolio of 198 engines, aircraft, and related equipment for other parties. The company was founded in 1985 and is headquartered in Coconut Creek, Florida.