Willis Lease Finance Corporation, along with its subsidiaries, is a lessor and services commercial aircraft and aircraft engines. The Company operates in two segments: Leasing and Related Operations, and Spare Parts Sales. The Leasing and Related Operations segment involves acquiring and leasing, primarily pursuant to operating leases, commercial aircraft, aircraft engines and other aircraft equipment and the selective purchase and resale of commercial aircraft engines and other aircraft equipment and other related businesses. The Spare Parts Sales segment involves the purchase and resale of after-market engine parts, whole engines, engine modules and portable aircraft components. Also, it provides end-of-life solutions for the surplus aircraft and engines, as well as managing the full life cycle of its lease assets. Its subsidiaries include WEST Engine Funding LLC, Willis Aeronautical Services, Inc., Coconut Creek Aviation Assets LLC, Facility Engine Acquisition LLC, and others.