Everyone who owns a car has heard about car leases; what a lot of people don't realize is that many airlines lease some or all of their aircraft. GE Capital Aviation Services (GECAS), the business aircraft finance unit of GE Capital Corporation (GECC), has the largest fleet of planes for leasing in the world -- about 1,800 aircraft including widebodies, narrowbodies, freight planes, and regional jets. GECAS also leases and offers financing to customers who wish to buy aircraft, engines, and spare parts. To top it off, the unit also provides pilot training services. GECAS counts more than 245 airline customers in some 75 countries.