GECAS and ILFC dwarf even the largest airlines in terms of fleet size. They are the biggest and most important customers for commercial planemakers Boeing Co. and Airbus, a unit of European aerospace company EADS.
The firms are playing a large role in airlines' expansion, giving carriers a way to operate the newest planes without massive capital outlays.

Many airlines, especially smaller start-up carriers and those outside the United States, have relied on leasing firms to build up their fleets to meet the new demand, as passengers return to the skies after economic slowdowns and concerns after the attacks of September 11, 2001.

Terra Firma TERA.UL, which ranks as the world's 15th-largest private equity firm, is buying Pegasus from its senior management and from funds managed by Oaktree Capital Management.
San Francisco-based Pegasus owns 82 aircraft, manages 94 planes and has 37 planes on order, including Boeing's new 787 Dreamliner, Terra Firma said. AWAS leases 134 aircraft to airlines around the world.

Terra Firma, which has offices in London and Frankfurt, and is run by British financier Guy Hands, has been trying to build on its aircraft leasing business since buying Dublin-based AWAS in March 2006.
The firm was among those that expressed interest earlier this year in bidding for Italian carrier Alitalia.