AerCap is the world's largest aviation lessor, owning and leasing aircraft, engines, and helicopters to airlines and other aviation operators globally. The core business is straightforward: AerCap buys aircraft from Airbus and Boeing, then leases them to airlines under multi-year operating leases. Airlines prefer leasing over ownership because it reduces capital requirements and gives fleet flexibility. AerCap serves roughly 300 customers across all major regions, with Asia/Pacific, Europe, and North America as the largest markets. Beyond commercial aircraft, AerCap runs three complementary businesses: engine leasing (the world's largest spare engine lessor, with over 1,200 owned, managed, and on-order engines), helicopter leasing through Milestone Aviation (~335 helicopters for offshore oil & gas, search and rescue, and emergency medical), and a cargo aircraft business including a 777-300ER freighter conversion program. AerCap makes money primarily on lease rents, gains from selling aircraft out of its portfolio, and maintenance revenue collected from lessees. The company funds its fleet with unsecured notes and bank debt, targeting 2.7x debt-to-equity leverage. A key portfolio discipline is what management calls the "barbell" approach — concentrating on either new-technology aircraft (A320neo, 737 MAX, 787) or end-of-life assets, and avoiding mid-life older-technology planes that face declining demand. AerCap grows organically through OEM orders, sale-leaseback transactions with airlines, and bilateral acquisitions, and has also historically expanded through large M&A deals.